MEDICAL    tSCH<S>€>L 


FROM  THE  LIBRARY  OF 
FRANK  BRANSON  PETRIE,  M.D. 


LABORATORY  TEACHING: 


OE, 


PROGRESSIVE  EXERCISES  IN  PRACTICAL 
CHEMISTRY. 


WORKS  ON  CHEMISTRY 

PUBLISHED  BY 

LINDSAY  &  BLAKISTON, 

PHILADELPHIA. 


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LABORATORY  TEACHING 


PROGRESSIVE  EXERCISES 


PEACTICAL  CHEMISTRY. 


BY 

CHARLES  LOUDOKtELDXAM, 

PROFESSOR   OF    CHEMISTRY    IN    KING'S    COLLEGE,    LONDON  J 

IN  THE  DEPARTMENT  OF  ARTILLERY  STUDIES,  WOOLWICH,  AND  IN  THE 

ROYAL  MILITARY  ACADEMY.,  WOOLWICH. 


FOURTH  EDITION, 

WITH 

EIGHTY-NINE  ILLUSTRATIONS. 


187? 


PHILADELPHIA: 
LINDSAY    AND    BLAKISTON 


COr.  LINS,    PRINTER. 


PREFACE 


TO 


THE  FOURTH  EDITION 


THE  most  important  alteration  in  the  present  Edition  is 
the  introduction  of  the  formulae  representing  the  various 
chemical  compounds  described  in  the  Notes  to  the  Tables. 
The  formulae  are  those  now  generally  employed  by  chemical 
writers  and  teachers  in  this  country. 

The  verbal  description  of  the  composition  in  the  Tables 
of  Common  Compounds  of  the  several  metals  has  not  been 
altered  so  as  to  bring  it  into  perfect  harmony  with  the 
formulae,  since  the  description  there  given  generally  informs 
the  learner  what  substances  can  be  obtained  by  the  decom- 
position of  the  Common  Compounds,  which  is  not  so  easily 
to  be  ascertained  by  an  inspection  of  the  formulae. 

For  example,  the  composition  of  saltpetre  is  described  at 
page  81,  as  Potash  (Potassium  and  Oxygen)  and  Nitric 
Acid,  whilst  the  formula  KNO3  does  not  indicate  the  pre- 
sence of  potash  (K2O)  or  of  nitric  acid  (HNO3) ;  but  both 
these  substances  are  obtainable  from  saltpetre  by  very 


Vi  PREFACE    TO    THE    FOURTH    EDITION. 

simple  chemical  operations,  and  saltpetre  may  be  produced 
by  causing  them  to  act  upon  each  other. 

It  is  true  that  similar  reasoning  would  justify  the  state- 
ment that  common  salt  contained  soda  and  hydrochloric  acid 
instead  of  sodium  and  chlorine,  but  the  Author  feels  that 
an  endeavor  to  be  absolutely  consistent  would  injure  the 
practical  usefulness  of  so  small  a  book. 

May,  1879. 


PREFACE 


TO 


THE   FIRST   EDITION 


THIS  work  is  intended  for  use  in  the  Chemical  Laboratory 
by  those  who  are  commencing  the  study  of  Practical 
Chemistry.  It  contains — 

(1)  A  series  of  simple  Tables  for  the  analysis  of  unknown 
substances  of  all  kinds  (not  excepting  organic  bodies) 
which   are  known    to  be   single  substances,   and  not 
mixtures  : 

(2)  A  brief  description  of  all  the  practically  important 
single   substances  likely  to  be  met  with  in  ordinary 
analysis,  by  which    the   learner    may    satisfy  himself 
that  his  results  are  correct,  and  may  at  the  same  time- 
become  acquainted  with  the  leading  properties  of  the 
most  important  chemicals,  and  with  the  foreign  sub- 
stances which  they  are  liable  to  contain  : 

(3)  Simple  directions  and  illustrations  relating  to  Che- 
mical   Manipulation,    not    collected   into   a   separate 
chapter,  but   given  just  where    the  learner   requires 
them  in  the  course  of  analysis : 


Vlll  PREFACE    TO    THE    FIRST    EDITION. 

(4)  A  system  of  Tables    for  the  detection  of  unknown 
substances  with  the  aid  of  the  Blowpipe  : 

(5)  Short  instructions  upon  the  purchase  and  preparation 
of  the  tests,  intended  for  those  who  have  not  access  to 
a  Laboratory. 

The  book  does  not  presuppose  any  knowledge  of  Che- 
mistry on  the  part  of  the  pupil,  and  does  not  enter  into  any 
theoretical  speculations. 

It  dispenses  with  the  use  of  all  costly  Apparatus  and 
Chemicals,  and  is  divided  into  separate  Exercises  or  Lessons, 
with  Examples  for  Practice,  to  facilitate  the  instruction  of 
large  Classes. 

The  Author  hopes  that  it  will  be  found  to  contain  all  the 
Practical  Chemistry  required  for  the  various  Examinations, 
except  for  the  highest  Science  degrees,  such  as  the  B.Sc. 
and  D.Sc.  of  the  University  of  London. 

The  method  of  instruction  here  followed  has  been  adopted 
by  the  Author  after  twenty-three  years'  experience  as  a 
teacher  in  the  Laboratory,  by  which  he  has  been  led  to 
conclude  that  a  knowledge  of  Analytical  Chemistry,  or  the 
power  of  discovering  the  nature  of  unknown  substances,  is 
the  first  and  often  the  only  requirement  of  the  great  majority 
of  learners,  and  that,  independently  of  the  technical  value  of 
such  knowledge,  its  acquisition  forms  a  most  valuable  part  of 
education,  by  cultivating  the  powers  of  observation,  and 
affording  excellent  examples  of  the  application  of  logical 
reasoning  in  practical  work. 

The  ordinary  method  of  teaching  Analytical  Chemistry,  by 
causing  the  pupil  to  study  the  Reactions  or  tests  for  all  the 
metals  and  non-metallic  bodies,  before  he  proceeds  to  exa- 


PREFACE    TO    THE    FIRST    EDITION.  IX 

mine  an  unknown  substance,  does,  without  doubt,  lay  the 
best  foundation  for  a  thorough  knowledge  of  this  branch  of 
Science,  when  a  student  has  time  at  his  command,  and  can 
commit  to  memory  a  large  number  of  independent  facts 
which  receive  no  immediate  application.  But,  within  the 
Author's  experience,  many  students  become  wearied  with 
the  monotonous  routine  of  this  system,  and  are  prevented 
from  persevering  in  the  study. 

Moreover,  such  a  system,  although  teaching  the  student 
to  discover,  for  example,  that  a  given  salt  contains  potassium 
and  nitric  acid,  fails  often  to  instruct  him  that  these  consti- 
tute saltpetre,  and  does  not  acquaint  him  with  the  appear- 
ance and  other  properties  of  saltpetre,  by  observing  which 
he  may  be  sure  that  his  analysis  is  correct.  For  want  of 
such  an  acquaintance  with  the  properties  of  the  common 
salts,  a  student  well  skilled  in  the  mere  detection  of  bases 
and  acids  will  sometimes  fall  into  .the  most  absurd  mistakes 
as  to  the  nature  of  a  substance  under  examination. 

Those  students  who  can  afford  the  time  are  strongly 
recommended  to  perform  every  experiment  described  in  the 
book,  with  the  known  substances,  before  attempting  the 
examination  of  an  unknown  substance. 

April,  1869. 

*^*  A  List  of  the  Apparatus  and  Chemicals  required  for 
the  Course  will  be  found  at  pp.  228-243. 


CONTENTS. 


PARAGRAPHS  1 — 31. — Analysis  of  substances  containing  a  single 
metal.  Solution.  Filtration.  Precipitation.  Division  of  the 
metals  into  groups.  Identification  of  the  individual  members 
of  each  group.  Description  of  the  metals  and  of  their  chief 
oxides  and  salts. 

PARAGRAPHS  82 — 121. — Analysis  of  substances  containing  a  single 
inorganic  acid  or  non-metallic  body.  Expulsion  of  acids  from 
their  compounds  by  sulphuric  and  hydrochloric  acids.  Pre- 
cipitation of  acids  by  barium  nitrate,  silver  nitrate,  calcium 
chloride  and  ferric  chloride.  Description  of  the  principal  in- 
organic acids. 

PARAGRAPHS  122 — 141. — Analysis  of  substances  insoluble  in  water 
and  acids.  Fusion.  Description  "of  the  principal  insoluble 
substances. 

PARAGRAPHS  142 — 162. — Analysis  of  substances  which  may  contain 
one  metal  and  one  organic  acid.  Description  of  the  principal 
organic  acids,  and  their  common  salt. 

PARAGRAPHS  163 — 171. — Detection  of  the  principal  vegetable  alka- 
loids. Identification  of  caffeine,  morphine,  brucine,  strychnine, 
quinine,  narcotine,  and  cinchonine. 

PARAGRAPHS  172 — 176a. — Identification  of  the  more  common  organic 
substances  characterized  by  color  or  odor.  Indigo.  Picric  acid. 
Caramel.  Carbolic  acid.  Chloral  hydrate. 

PARAGRAPHS  177 — 205. — Examination  of  a  solid  organic  substance 
having  no  definite  color  or  odor.  Identification  of  cane-sugar, 
grape-sugar,  milk-sugar,  urea,  pyrogalline,  salicine,  albumen, 
starch,  dextrine,  gum,  gelatine,  soap,  stearine,  stearic  acid, 
palmitic  acid,  cholesterine,  rosin,  naphthaline,  palmitine,  sper- 
maceti, wax,  and  paraffine. 


Xll  CONTENTS. 

PARAGKAPHS  206 — 229. — Examination  of  a  liquid  organic  substance 
having  a  very  distinct  odor.  Identification  of  alcohol,  methy- 
lated spirit,  wood-naphtha,  acetone,  aldehyde,  nicotine,  butyric 
acid,  valerianic  acid,  aniline,  ether,  chloroform,  oil  of  bitter 
almonds,  nitrobenzole,  and  benzole.  Distillation. 

PARAGRAPHS  230 — 234. — Examination  of  a  liquid  organic  substance 
having  no  distinct  odor.  Identification  of  glycerine,  lactic  acid, 
oleine,  and  oleic  acid. 

PARAGRAPH  235. — Examination  of  a  solid  organic  substance  about 
which  nothing  is  known  but  that  it  is  a  single  substance  and 
not  a  mixture. 

PARAGRAPH  236. — Examination  of  a  liquid  organic  substance  about 
which  nothing  is  known  but  that  it  is  a  single  substance  and 
not  a  mixture. 

PARAGRAPH   237. — Examination   of    a   solid    substance  of    which 
-  nothing  is  known  but  that  it  is  a  single  substance  and  not  a 
mixture. 

PARAGRAPH  238. — Examination  of  a  liquid  of  which  nothing  is 
known  but  that  it  is  a  solution  of  a  single  substance  and  not  a 
mixture. 

PARAGRAPH  239. — Examination  of  an  organic  substance  which  is 
known  to  be  included  in  the  list  given  for  the  1st  M.B.  Exami- 
nation of  the  University  of  London. 

PARAGRAPHS  240 — 282. — Detection  of  metals  by  the  blowpipe. 
Reduction  on  charcoal.  Borax-Beads.  Colored  flame  test. 
Cobalt  test.  Sublimation  test.  Cupellation. 

PARAGRAPHS  283 — 307. — Detection  of  non-metals  or  acids  by  the 
blowpipe.  Heating  with  bisulphate  of  potash. 

PARAGRAPHS  308 — 363. — Alphabetical  list  of  test  used  in  analysis. 
PARAGRAPH  364. — Apparatus  required  in  qualitative  analysis. 
APPENDIX. — Qualitative  Analysis  of  Gunpowder. 


LABORATORY  TEACHING; 

OR, 

PROGRESSIVE  EXERCISES  IN  PRACTICAL 
CHEMISTRY. 


INTRODUCTION. 

THE  instructions  given  in  this  work  are  intended  to  enable 
the  student  to  discover  the  nature  of  most  of  the  chemical 
compounds  in  common  use. 

When  nothing  is  known  about  the*  substance,  its  examina- 
tion must  be  commenced  according  to  Exercise  XIII.  (para- 
graph 237)  if  it  be  a  solid,  or  XIV.  (paragraph  238)  if  it  be 
a  liquid. 

But  it  is  better  for  beginners  to  confine  their  attention  to 
ordinary  inorganic  salts,  which  may  be  commenced  by  Table 
A.  For  the  first  few  lessons,  the  detection  of  the  metal,  by 
Tables  A  to  F,  will  suffice. 

Having  detected  the  metal,  the  student  should  turn  to  the 
description  of  that  metal  and  its  common  compounds,  and 
endeavor  to  name  the  unknown  body  under  examination. 

When  he  is  well  versed  in  the  detection  of  the  metal,  he 
may  proceed  to  discover  the  non-metallic  body  or  acid  which 
composes  the  other  portion  of  the  compound. 

In  many  cases,  where  a  substance  has  a  peculiar  color  or 
smell,  a  reference  to  that  color  or  smell  in  the  Index  may 
lead  to  its  identification. 
2 


14  INTRODUCTION. 

The  learner  will  find  it  advantageous  to  study  the  list  of 
the  principal  tests,  commencing  with  paragraph  308,  since 
he  will  there  find  the  formulae  expressing  their  composition, 
and  a  list  of  the  substances,  the  presence  of  which  is  indicated 
with  certainty  by  the  action  of  any  particular  test. 

The  numerals  inclosed  in  parentheses  in  each  Table  refer 
to  paragraphs  in  the  text,  and  it  will  be  found  absolutely 
necessary  to  refer  to  these  in  order  to  render  the  Tables 
serviceable. 

A  rough  note-book  should  be  provided,  in  which  every 
step  of  the  analysis  should  be  entered,  the  symbols  being 
employed  for  the  tests,  both  to  avoid  much  writing  and  to 
fix  their  composition  in  the  memory. 

A  Report  of  an  Analysis  is  appended  as  a  model. 


REPORT    OF    ANALYSIS. 


15 


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TABLE    OF    ATOMIC    WEIGHTS. 


The  subjoined  Table  indicates  the  relative  weights  of  the 
Elementary  Bodies  represented  by  the  symbols  composing 
the  formulae  given  in  this  work. 


Aluminium 

.     .     Al 

27-5 

Lead       .     . 

.     .     Pb 

207 

Antimony  . 

.     .     Sb 

122 

Magnesium 

.     .     Mg 

24-3 

Arsenic  .     . 

.     .     As 

75 

Manganese 

.     .     Mn 

55 

Barium  . 

.     .     Ba 

137 

Mercury 

.     .     Hg 

200 

Bismuth 

.     .     Bi 

210 

Nickel    .     . 

.     .     Ni 

59 

Boron     .     . 

.     .     B 

10-9 

Nitrogen     . 

.     .     N 

14 

Bromine 

.     .     Br 

80 

Oxygen 

.     .     O 

16 

Calcium 

.     .     Ca 

40 

Phosphorus 

.     .     P 

31 

Carbon  .     . 

.     .     C 

12 

Platinum    . 

.     .     Pt 

197-1 

Chlorine 

.     .     Cl 

35-5 

Potassium 

.     .     K 

.39-1 

Chromium  . 

.     .     Cr 

52-5 

Silicon   .     . 

.     .     Si 

28 

Cobalt    .     . 

.     .     Co 

59 

Silver     .     . 

.     .     Ag 

108 

Copper  .     . 

.     .     Cu 

63-5 

Sodium  .     . 

.     .     Na 

23 

Fluorine 

.     .     F 

19 

Strontium  . 

.     .     Sr 

87-5 

Gold       .     . 

.     .     Au 

196-6 

Sulphur 

.     .     S 

32 

Hydrogen   . 

.     .     H 

1 

Tin 

Sn 

118 

Iodine    .     . 

.     .     I 

127 

Tungsten    . 

.     .     W 

184 

Iron  . 

Fe 

56 

Zinc  . 

Zn 

65 

TABLE    A. 


17 


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18 


INSTRUCTIONS    ON    TABLE    A. 


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SOLUTION.       BOILING. 


19 


3.  To  dissolve  the  substance  for  analysis,\>\<\.c,Q  about  five 
grains  of  the  powdered  substance  (as  much  as  can  be  taken 
easily  on  the  end  of  the  large  blade  of  a  pocket-knife)  in  a 


Fia. 1. 


Test-tube  rack. 


Test-tul>e. 


Tube  cleaner. 


Fia.  2. 


test-tube  (fig.  1),  pour  upon  it  about  two  drachms  (two  tea- 
spoonfuls)  of  distilled  water,  shake  them  together,  and  if 
necessary,  boil  the  water 
over  the  flame  of  a  spirit- 
lamp  (fig.  2)  or  a  gas-burner ; 
in  the  latter  case,  holding  the 
tube  a  little  above  the  flame, 
so  as  not  to  smoke  it  (figs.  3 
and  4).  The  tube  may  be 
held  in  a  band  of  folded  pa- 
per when  it  is  necessary  to 
boil  for  some  time. 


Fia.  3. 


Fro.  4. 


20 


SOLUTION.       FILTRATION. 


If  the  substance  does  not  appear  to  diminish  in  quantity, 
it  may  be  set  down  as  undissolved  by  the  water. 

Fl°5-  Should  there  be  any 

doubt,  filter  the  solution 
(4),  catch  a  drop  of  it 
upon  a  piece  of  thin 
window  glass,  and  eva- 
porate it  at  a  gentle  heat 
(fig.  5).  If  no  consider- 
able residue  of  solid 
matter  is  left,  the  substance  may  be  considered  insoluble. 

Should  water  have  failed  to  dissolve  the  substance,  pour 
off  the  water  so  as  to  leave  the  powder,  if  possible,  at  the 
bottom  of  the  tube  ;  pour  upon  it  about  a  drachm  of  diluted 
hydrochloric  acid,  and  boil  if  necessary. 

If  the  substance  be  insoluble  in  hydrochloric  acid,  boil  a 
fresh  portion,  in  another  tube,  with  diluted  nitric  acid,  and 
should  this  fail  to  dissolve  it,  add  a  few  drops  of  nitric  acid  to 
the  hydrochloric  acid  previously  employed,  and  again  boil. 

Substances  which  are  insoluble  in  water  and  acids  must  be 
examined  according  to  Table  I. 

4.  To  filter  a  solution. — Take  a  circular  piece  of  white 
filtering  (blotting)  paper,  three  or  four  inches  in  diameter, 
fold  it  neatly  as  in  fig.  G,  open  it  so  as  to  form  a  cone,  place  it 


Fia. 


FIG.  7. 


TESTING.       EXCESS.  21 

in  a  funnel,  moisten  it  with  distilled  water,  support  the  fun- 
nel in  a  test  tube,  as  in  fig.  7,  and  pour  upon  it  the  solution 
to  be  filtered.  Should  the  funnel  happen  to  fit  air-tight  into 
the  test-tube,  interpose  a  little  piece  of  wood  or  paper  to 
leave  a  passage  for  the  air. 

If  the  first  filtration  does  not  clear  the  liquid,  it  must  be 
poured,  back  through  the  same  filter. 

5.  Addition  of  tests  to  liquids — As  a  general  rule,  tests 
are  gently  poured,  drop  by  drop,  down  the  side  of  the  test- 
tube  (fig.  8),  which  is 

gently  shaken,  until  FlG<  8- 

either  the  expected 
effect  is  produced,  or 
a  reasonable  propor- 
tion of  the  test  has 
been  added  without 
any  result.  The  stop- 
per of  the  bottle 

should  not  be  laid  upon  the  table,  but  should  be  held  be- 
tween the  second  and  third  fingers  of  the  left  hand,  as  in  fig. 
8,  and  the  label  of  the  bottle  should  always  be  upwards. 

Excess In  cases  where  the  test  is  to  be  added  in  excess,  the 

addition  is  continued  until  no  further  effect  is  produced  by 
adding  another  portion,  and  until  some  conspicuous  property 
of  the  test  becomes  evident  in  the  liquid  to  which  it  is  added. 

Thus,  Hydrosulphuric  Acid  is  known  to  be  in  excess  when 
a  strong  smell  of  it  is  perceived  at  the  mouth  of  the  test-tube 
after  closing  the  tube  with  the  thumb,  and  violently  shaking 
it.  Since  the  strongest  hydrosulphuric  acid  only  contains 
about  three  times  its  volume  of  sulphuretted  hydrogen  gas,  it 
is  necessary  to  add  this  test  in  large  quantity,  often  amount- 
ing to  three  or  four  times  the  volume  of  the  liquid  to  be 
tested.  Again,  Ammonia  would  be  known  to  have  been 
added  in  excess  by  its  powerful  odor,  but  if  the  liquid  tested 
be  strongly  acid,  it  is  not  advisable  to  close  the  tube  with  the 
thumb  when  shaking  it,  as  the  action  of  ammonia  upon 


22 


STIRRING-RODS. 


FIG.  9. 


strongly  acid  liquids  is  of  a  violent  character.     The  solution 

may  be  mixed  by  pouring  from  one  tube  into  another. 

6.  Precipitation  promoted  by  stirring. — The  formation 

of  the  precipitate  of  phosphate  of  ammonia  and  magnesia  is 

much  facilitated  by  stir- 
ring the  liquid  with  a 
glass  rod,  or,  still  better, 
by  rubbing  the  rod  against 
the  side  of  the  tube  (fig. 
9),  the  latter  being  held 
in  an  inclined  position, 
and  the  rod  held  short  so 
that  it  cannot  possibly  be 

thrust  through  the  bottom  of  the  tube. 


To  make  a  stirring-rod — The  glass  rod  used  for  this  pur- 
pose should  be  about  six 
inches  long,  and  round- 
ed at   both  ends.     To 
make  it  from  one  of  the 
long  glass  canes  sold  at 
the  glass-house,  cut  off 
six  inches  by  making 
a  deep'  scratch  with  a 
three-cornered  file,  and 
breaking  the  rod  at  this  point 
by   a    sharp   jerk   (fig.    10). 
Fuse  each  end  in  the  extreme 
point  of  the  blowpipe  flame 
(fig.    11)   till    well  rounded. 
The  glass  must  not  be  intro- 
duced into  the  inner  part  of 
the  flame,  or  it  will  be  per- 
manently   blackened,     from 
the  separation  of  lead  in  the 
metallic  state. 


FIG.  11. 


MAGNESIUM    AND    ITS    COMPOUNDS.  26 

NOTES  TO  TABLE  A. 

rl.  The  deposition  of  sulphur  from  the  hydrosulphuric 
acid  may  be  due  to  a  variety  of  causes  ;  for  example,  to  the 
presence  of  nitrous  acid  derived  from  the  nitric  acid  em- 
ployed in  dissolving  the  substance  ;  to  free  chlorine  ;  ferric 
chloride  (perchloride  of  iron)  ;  sulphurous  acid ;  chromic 
acid. 

8.  Chloride  of  ammonium  is  added  to  prevent  the  prema- 
ture precipitation  of  magnesia,  and  should  be  added  in  con- 
siderable quantity.     A  solution  containing  a  salt  of  magnesia 
yields,  on  addition  of  ammonia,  a  precipitate  of  hydrate  of 
magnesia,  but  if  chloride  of  ammonium  be  previously  added, 
no  precipitate  is  formed. 

Should  the  chloride  of  ammonium  itself  produce  a  preci- 
pitate, before  the  ammonia  is  added,  it  probably  consists  of 
silica,  and  the  substance  under  examination  is  likely  to  be 
silicate  of  potash  or  soda  (77,  80). 

9.  Should  the  precipitate  produced  by  phosphate  of  soda 
be  flocculent  instead  of  granular  and  crystalline,  it  is  proba- 
ably  not  caused  by  magnesium,  but  by  aluminium  or  calcium 
-which  ought  to  have  been  detected  in  column  3  or  4. 

In  determining  the  particular  form  in  which  the  magne- 
sium is  present  in  the  substance  under  examination,  assist- 
ance will  be  derived  from  the  following  statements. 

Metallic  Magnesium,  Mg,  is  silver-white,  burns  easily  in 
air,  with  a  very  brilliant  light,  and  is  dissolved,  with  effer- 
vescence, when  boiled  with  chloride  of  ammonium. 

COMMON  COMPOUNDS  OF  MAGNESIUM. 

Names.  Composition. 

Calcined  magnesia  Magnesium,  oxygen. 

Common  magnesia,  or  )      -.T 

Basic  carbonate  of  magnesia  }      Magnesia,  carbonic  acid,  water. 

Epsom  salts,  or.  )      ,, 

Sulphate  of  magnesia  }      MaSnesia>  sulphuric  acid,  water. 

Magnesite,  or  ^  )      ,r 

Carbonate  of  magnesia  Magnesia,  carbonic  acid. 


24  EXAMPLES    FOR    PRACTICE. 

Calcined  Magnesia,  MgO,  is  a  white  earthy  powder,  in- 
soluble in  water,  and  dissolved  by  hydrochloric  acid,  with 
little  or  no  effervescence. 

Basic  Carbonate  of  Magnesia,  3MgC03,MgH2O2,  is  simi- 
lar, but  effervesces  rapidly  with  hydrochloric  acid. 

Magnetite,  MgCO3,  is  found  in  white  earthy  lumps  which 
dissolve,  with  effervescence,  in  hydrochloric  acid. 

Sulphate  of  Magnesia,  MgS04,7Aq,  forms  needle-like 
crystals,  recognized  by  their  bitter  taste,  easily  dissolved  by 
water,  and  copiously  precipitated  by  nitrate  or  chloride  of 
barium. 

10.  Examples  for  Practice  in  Table  A The  following 

substances  will  afford  good  practice  in  this  Table,  especially 
if  they  are  presented  to  the  student  as  puzzles,  distinguished 
only  by  letters  or  numbers. 


Sulphate  of  magnesia 
Sulphate  of  iron 
Acetate  of  lead 
Arsenious  acid 
Carbonate  of  lime 
Sulphate  of  zinc 


Corrosive  sublimate 
Sulphate  of  copper 
Carbonate  of  magnesia 
Sulpliide  of  antimony 
Metallic  tin. 


TABLE    B. 


25 


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26  SILVER    AND    ITS    COMPOUNDS. 

NOTES  TO  TABLE  B. 

12.  Confirmatory  Tests  for  Silver,  to  be  applied  to   the 
original  solution. 

Potash  produces  a  brown  precipitate  of  oxide  of  silver. 

Bichromate  of  Potash  produces  a  red  precipitate  of  chro- 
mate  of  silver. 

Chloride  of  Ammonium  produces  a  white  precipitate  of 
chloride  of  silver. 

If  the  original  substance  be  Metallic  Silver,  Ag,  it  will  be 
recognized,  partly  by  its  external  characters,  partly  by  its 
refusing  to  dissolve  in  hydrochloric  acid,  but  dissolving  easily 
in  nitric  acid.  If  greater  certainty  be  desired,  it  may  be 
examined  by  the  blowpipe  (2G4). 

COMMON  COMPOUNDS  OF  SILVER. 

Names.  Composition. 

•    Nitrate  of  silver,  or      )      r\   •  ?      c    M 

Lunar  caustic  }      Oxule  of  Sllver'  mtnc  acicL 

Chloride  of  silver  Silver,  chlorine. 

Nitrate  of  Silver,  AgNO3,  is  sold  either  in  flat,  tabular, 
transparent  crystals,  or  in  opaque  cylindrical  sticks  made  by 
fusing  the  crystals.  It  is  dissolved  very  readily  by  cold 
water,  and  if  filter-paper  be  moistened  with  the  solution,  and 
exposed  to  light,  especially  to  sunlight,  it  assumes  a  black 
metallic  appearance. 

Chloride  of  Silver,  AgCl,  is  insoluble  in  water  and  in 
acids,  and  will  therefore  not  come  under  consideration  at 
present  (128). 

13.  Confirmatory  Tests  for  Mercury  as  a  mercurous  com- 
pound, to  be  applied  to  the  original  solution. 

Potash  produces  a  black  precipitate  of  mercurous  oxide, 
Hg20. 

Metallic  Copper  becomes  silvery  from  the  deposition  of 
mercury. 


MERCURY  AND  ITS  COMPOUNDS.  27 

Protochloride  of  Tin  (Stannous  chloride),  added  in  excess, 
produces  a  gray  precipitate  of  finely  divided  mercury. 
Metallic  Mercury  (quicksilver)  would  be  known  at  once. 

COMMON  MERCUROUS  COMPOUNDS. 

Names.  Composition. 

Mo_s  chloride,  or 


Calomel,  HgCl  or  Hg2Cl2,  is  commonly  sold  as  a  white 
heavy  powder,  with  a  very  slight  shade  of  yellow.  Before 
being  ground  to  powder,  it  forms  a  translucent  fibrous  mass. 
It  is  not  dissolved  by  water  or  dilute  hydrochloric  acid,  and 
not,  unless  boiled,  by  dilute  nitric  acid  ;  a  mixture  of  the 
two  acids  dissolves  it  more  readily  when  boiled.  Calomel 
is  easily  known  by  its  becoming  black  when  shaken  with 
potash  or  with  lime-water,  and  dark  gray  when  shaken  with 
ammonia  (250). 

Protonitrate  of  Mercury,  HgN03,Aq.,  is  sold  in  transpa- 
rent prismatic  crystals,  which  are  decomposed  when  treated 
with  water,  a  yellow  basic  nitrate  of  mercury  being  separated. 

14.  Confirmatory  Tests  for  Lead,  to  be  applied  to  the 
original  solution. 

Hydrochloric  Acid  produces  a  white  precipitate  of  lead 
chloride,  which  dissolves  on  boiling,  and  is  deposited  in  fine 
needles  on  cooling. 

Dilute  Sulphuric  Acid  produces,  especially  on  stirring,  a 
white  precipitate  of  sulphate  of  lead,  not  dissolved  by  an 
excess  of  the  acid,  and  soon  depositing  as  a  powder  at  the 
bottom  of  the  tube. 

Hydrosulphuric  Acid  produces  a  purplish  black  precipi- 
tate of  sulphide  of  lead. 

Bichromate  of  Potash  produces   a  yellow  precipitate  of 


28 


LEAD  AND  ITS  COMPOUNDS. 


chromate  of  lead.  If  the  original  substance  be  Metallic  Lead, 
Pb,  it  will  be  recognized  by  its  softness,  and  by  its  making 
a  black  streak  on  paper  ;  it  is  insoluble  in  hydrochloric  acid, 
but  dissolves  when  boiled  with  dilute  nitric  acid;  the  solu- 
tion gives  a  white  precipitate  with  excess  of  ammonia,  and 
a  black  precipitate,  with  a  purplish  shade,  on  addition  of 
hydrosulphuric  acid. 

COMMON  COMPOUNDS  OF  LEAD. 


Names. 


Peroxide  of  lead, 


} 


Composition. 


Lead,oXygen. 
Lead,  oxygen. 


Carbonate  of  lead,  or 
White  lead 

Chroinate  of  lead,  or 
Chrome  yellow 

Nitrate  of  lead 
Chloride  of  lead 
Iodide  of  lead 
Oxychloride  of  lead 
Sulphate  of  lead 

Sulphide  of  Ic^,  or 


~    .  -,      f  ,      -,          n      .        ., 

°xlde  of  lead>  carbonic  acid,  water. 


/-v'-i      riji         •        -3 
°xlde  of  lead'  chromic  acl(L 

Oxide  of  lead,  nitric  acid. 

Lead,  chlorine. 

Lead,  iodine. 

Lead,  oxygen,  chlorine. 

Oxide  of  lead,  sulphuric  acid. 

Lead;  sulpllul, 


Massicot,  or  Oxide  of  Lead,  PbO,  is  a  yellow  powder, 
which  is  insoluble  in  water,  and  becomes  white  when  boiled 
with  hydrochloric  acid,  being  converted  into  chloride  of  lead, 
which  partly  dissolves,  and  is  deposited  in  needle-like  crys- 
tals on  cooling.  Diluted  nitric  acid  dissolves  massicot  when 
gently  heated. 

Litharge  is  the  same  oxide  of  lead,  which  has  been  melted, 
and  is  sold  in  pinkish-brown  or  buff  scales  or  powder.  The 
action  of  water  and  acids  upon  it  is  similar  to  that  upon 
massicot. 


LEAD    COMPOUNDS.  29 

Minium,  Pb3O4,  is  a  bright  red  powder,  which  is  not 
affected  by  water,  but  evolves  the  smell  of  chlorine  when 
boiled  with  hydrochloric  acid,  and  is  slowly  converted  into 
chloride  of  lead.  Dilute  nitric  acid  only  partly  dissolves  it, 
leaving  a  brown  powder  (peroxide  of  lead). 

Peroxide  of  Lead,  or  Binoxide  of  Lead,  PbO2,  is  a  dark 
brown  powder,  which  is  insoluble  in  water  and  in  nitric  acid, 
but  dissolves  slowly  in  boiling  hydrochloric  acid,  giving  off 
the  smell  of  chlorine,  and  forming  chloride  of  lead,  which 
crystallizes  in  needles  from  the  solution  as  it  cools. 

Acetate  of  Lead,  Pb2C2H3O23Aq.,  forms  white  needle- 
like  crystals,  which  have  a  faint  odor  and  an  intensely  sweet 
taste.  When  treated  with  water  it  dissolves,  but  yields  a 
milky  solution,  especially  with  common  water,  from  the 
presence  of  a  little  carbonate  of  lead,  formed  from  the  car- 
bonic acid  contained  in  the  water ;  nitric  acid  clears  it  up  at 
once.  When  acetate  of  lead  is  heated  on  the  point  of  a 
knife,  or  on  a  slip  of  glass,  it  melts,  and  gives  off  an  inflam- 
mable vapor  with  a  very  peculiar  smell,  leaving  a  gray  resi- 
due composed  of  carbon  and  minute  globules  of  metallic 
lead,  easily  changing  to  yellow  oxide  of  lead. 

Perchloride  of  iron  (ferric  chloride),  added  to  a  solution 
of  acetate  of  lead,  produces  a  white  precipitate  of  chloride 
of  lead,  and  a  red  solution  of  ferric  acetate,  which  is  clearly 
seen  after  the  precipitate  has  subsided. 

White  Lead,  or  Basic  Carbonate  of  Lead,  2PbCO3,PbH2O2, 
is  a  heavy  earthy  powder,  soon  becoming  gray  when  exposed 
to  air,  from  the  action  of  sulphuretted  hydrogen.  It  is  in- 
soluble in  water,  and  effervesces  with  hydrochloric  acid,  dis- 
solving when  heated,  as  chloride  of  lead,  which  crystallizes 
in  needles  on  cooling.  Dilute  nitric  acid  easily  dissolves 
carbonate  of  lead,  with  effervescence  caused  by  the  escape 
of  carbonic  acid  gas.  When  heated  on  a  knife,  or  slip  of 
glass,  it  becomes  yellow. 

Chromate  of  Lead,  PbCrO4,  is  commonly  sold  as  a  bright 
yellow  or  orange  red  powder  or  cake — (the  orange  chrome 


30  LEAD    COMPOUNDS. 

is  the  basic  cliromate  or  dichromate  of  lead,  PbCrO4,PbO)  ; 
but  fused  cliromate  of  lead  has  a  brown  color.  It  is  insolu- 
ble in  water,  but  dissolves  slowly  when  boiled  with  strong 
hydrochloric  acid,  evolving  chlorine  and  yielding  a  green 
solution.  If  it  be  heated  with  hydrochloric  acid  and  a  little 
alcohol,  a  bright  green  solution  of  chlorides  of  chromium 
and  lead  is  produced,  which  deposits  crystals  of  chloride  of 
lead  on  cooling.  Nitric  acid  scarcely  affects  cliromate  of 
lead.  If  the  yellow  cliromate  of  lead  be  heated  on  a  knife, 
or  slip  of  glass,  its  color  changes  to  a  red-brown. 

Nitrate  of  Lead,  Pb2NO3,  forms  hard  white  crystals, 
having  a  sweet  taste.  It  dissolves  in  water,  but  not  easily 
unless  heated.  When  heated  on  a  knife,  or  slip  of  glass,  it 
crackles  or  decrepitates  violently.  If  previously  powdered, 
to  prevent  its  flying  off,  it  evolves  suffocating  brown  fumes 
(nitric  peroxide),  and  leaves  a  yellow  or  red  residue. 

Chloride  of  Lead,  PbCl2,  is  a  white  powder,  sometimes 
crystalline,  which  dissolves  slowly  when  boiled  with  water, 
the  solution  easily  depositing  crystals  on  cooling. 

Iodide  of  Lead,  PbI2,  is  a  bright  yellow  powder,  which 
dissolves  sparingly  in  boiling  water,  but  more  readily  on 
adding  a  little  hydrochloric  acid,  yielding  a  colorless  solu- 
tion, which  deposits  brilliant  golden  scales  on  cooling.  When 
boiled  with  nitric  acid,  iodide  of  lead  gives  off  the  purple 
vapors  of  iodine. 

Oxychloride  of  Lead  is  either  white  (Pb2OCl2)  or  bright 
yellow  (Pb8O7Cl2),  according  to  the  mode  of  preparing  it. 
It  melts  easily  when  heated,  the  white  oxychloride  becoming 
yellow.  It  is  insoluble  in  water,  but  dissolves  sparingly 
when  boiled  with  hydrochloric  acid,  the  solution  depositing 
crystals  of  chloride  of  lead  on  cooling. 

Sulphate  of  Lead,  PbSO4,  is  a  white  powder,  which  does 
not  change  when  heated,  is  insoluble  in  water,  but  dissolves 
slowly  in  boiling  hydrochloric  acid,  the  solution  depositing 
crystals  of  chloride  of  lead  as  it  cools. 

Sulphide  of  Lead  or  Galena,  PbS,  is  a  dark,  gray,  heavy, 


LEAD    COMPOUNDS.  31 

metallic -looking  substance,  the  masses  of  which  may  be  easily 
split  or  cleaved  with  a  knife-blade  into  rectangular  fragments. 
Water  has  no  effect  upon  it,  and  diluted  hydrochloric  acid 
very  little,  but  nitric  acid  gradually  dissolves  it,  brown  fumes 
being  evolved,  resulting  from  the  decomposition  of  the  nitric 
acid.  Strong  hydrochloric  acid  also  dissolves  it  on  heating, 
producing  the  offensive  odor  of  hydrosulphuric  acid. 
Phosphate  of  Lead,  Pb32PO4,  is  described  at  (112). 


32 


TABLE    C. 


1 


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IOSULPHURIC  ACID. 

•r  Orange-red.  f 
?  of  Atnimoiiy.  Ttisulplride  of 

BONATE  OF  AMMONIA  (32). 

Undissolved. 

Ora 
Sulphide 
Probabl. 
Antimf. 

fl^fljf           1 

Hsmuth  or  Mercury. 

YDROCHLORIC  ACID, 

ree  parts. 

"    11    *S-1             -2* 

^  M         M§   £     • 

<£  fc  _•  .2  ^  £  ^            22 

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irellow. 
of  Tin.  Probable 
'  Tin,  as  a  stannic 
mud  (36,  37). 

r-( 

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WASHING    PRECIPITATES. 


33 


Fid.  12. 


Fia. 14. 


FIG. 13. 


EXPLANATIONS  AND  INSTRUCTIONS  ON 
TABLE  C. 

16.  To  wash  a  precipitate. — The  precipitate  having  been 
collected  upon  a  filter  (4)  may  be  washed  by  filling  the  filter 
twice  or  thrice  with  distilled  water,  and  allowing  it  to  run 

through.  A  washing-bottle  (fig.  12) 
will  be  of  great  assistance  in  washing 
precipitates,  the  stream  of  water  be- 
ing directed  so  as  to  wash  the  pre- 
cipitate from  the  sides  towards  the 
apex  of  the  filter. 

When  a  precipitate  is  very  heavy 
and    subsides    readily,    it    may    be 
washed  by  decapitation — that  is,   by 
Washing-bottle.    s}ia^ing  jt  Up  with  successive  quan- 
tities   of     distilled 
water,    which    are 
poured     off    when 
the  precipitate  has 
settled    down.      A 
wet  glass  rod,  held 
against  the  lip  of  the 
test-tube  (fig.   13), 
greatly  assists  in  de- 
canting the  liquid  without  disturbing  the  precipitate. 

17.  Heating  solid  substances  in  tubes — Ordinary 
test-tubes  should  not  be  used  for  this  purpose,  but 
much  smaller  tubes,  which  are  made,  with  the   help 
of  the    blowpipe,  from  a  piece  of  (German)  glass 
tube  free  from  lead,  of  the  size  represented  in  fig.  14. 
The  middle  of  this  piece  of  tube  is  softened  in  the 
blowpipe  flame  (fig.  15),  and  quickly  drawn  out  to 
form  two  tubes  connected  by  a  mere  thread  of  glass, 
which  is  then  detached  from  each  tube,  as  shown  at 
«,  leaving  the  finished  tube  of  the  shape  shown  at  b. 


34 


SOLIDS  HEATED  IN  TUBES. 

FIG. 15. 


FIG.  16. 


The  substance  to  be  heated  is  introduced  into  this  tube,  in 
very  small  quantity,  and  the  sides  of  the  tube  are  cleansed 

frc  m  adhering  particles  by 
rubbing  them  with  a  match. 
A  strap  of  folded  paper  (fig. 
16)  is  put  round  the  tube, 
which  is  then  held  in  the 
lower  part  of  the  flame  of  a 
gas-jet  (to  avoid  smoking  it), 
or  in  a  spirit-flame.  If  any 
moisture  should  condense  on 
the  sides  of  the  tube.,  incline 

its  mouth  downwards,  so  that  the  drops  may  not  run  back 
upon  the  heated  glass  and  crack  it.  If  it  be  necessary  to 
apply  a  more  intense  heat,  the  blowpipe  flame  may  be 
directed  on  to  the  bottom  of  the  tube. 

18.    To  ascertain  ivhether  a  solution  is  alkaline  or  acid, 


TIN    IDENTIFIED.  35 

dip  a  piece  of  red  or  blue  litmus-paper  into  it,  or  touch  the 
paper  with  a  glass  rod  dipped  in  the  liquid.  An  alkaline 
solution  changes  red  litmus  to  blue,  whilst  an  acid  solution 
reddens  the  blue  litmus-paper.  In  the  absence  of  test- 
paper  the  taste  may  of  course  be  relied  on  for  a  rough 
indication. 

NOTES  TO  TABLE  C. 

19.  Lead  is  liable  to  be  found  in  the  precipitate  produced 
by  hydrosulphuric  acid,  because  its  chloride  is  dissolved  to  a 
considerable  extent  by  water,  so  that  a  weak  solution  of  a 
salt  of  lead  is  not  precipitated  by  hydrochloric  acid. 

20.  The  mercuric  salts  generally  give,  on  addition  of  a 
little  hydrosulphuric  acid,  a  yellow  or  brownish  precipitate, 
which  passes  through  various  shades  on  adding  more  hydro- 
sulphuric  acid,  finally  becoming  black. 

21.  Solutions  of  copper  have  a  blue  or  green  color.     The 
blue  solutions  are  turned  green  by  hydrochloric  acid. 

22.  The  perchloride  of  mercury  (mercuric  chloride)  will 
give,  with  stannous  salts  or  protosalts' of  tin,  a  white  precipi- 
tate of  mercurons  chloride  (calomel)  or  a  gray  precipitate 
of  finely-divided  metallic  mercury,  accordingly  as  one-half 
or  the  whole  of  the  chlorine  is  abstracted  from  the  mercuric 
chloride  by  the  protosalt  of  tin. 

23.  Metallic   Tin,  Sn,  would  be  easily  known  by  its  be- 
coming converted  into  a  white  powder  (binoxide  of  tin)  when 
boiled  with  nitric  acid.     It  dissolves  slowly  when  boiled  with 
diluted  hydrochloric  acid,  and  rapidly  in  the  strong  acid 
yielding  a  solution  of  protochloride  of  tin  (or  stannous  chlo- 
ride), which  is  at  once  recognized  by  the  test  with  perchlo- 
ride of  mercury  mentioned  above  (22). 

For  the  common  protosalts  of  tin,  see  the  next  page. 


36  TIN  COMPOUNDS. 

COMMON  STANNOUS  COMPOUNDS,  OR  PKOTOSALTS  OF  TIN. 

Names.  Composition. 

Protocliloride  of  tin  or  )      rp.        ,  ,     . 

Salts  of  tin,  or  tin  crystals  }      * in'  clllorine,  water. 

Protosulpliide  of  tin,  or         )      m. 

Tin  pyrites  j      lm'  sulphur. 

Protochloride  of  Tin,  SnCl2,2Aq.,  usually  forms  needle- 
like  crystals  with  a  tinge  of  yellow.  Water  decomposes  it, 
forming  a  milky-white  oxychloride  of  tin.  Hydrochloric  acid 
dissolves  it  entirely. 

Tin  Pyrites,  SnS,  is  a  dark  gray  mineral  which  is  slowly 
dissolved  when  boiled  with  hydrochloric  acid,  evolving  the 
smell  of  hydrosulphuric  acid.  Boiling  nitric  acid  converts  it 
into  the  white  binoxide  of  tin. 

24.  The  precipitate  of  sulphate  of  lead  sometimes  forms 
only  after  the  lapse  of  some  minutes  in  highly  acid  solutions. 

25.  If  the  quantity  of  the  original  solution  is  very  limited, 
ammonia  may  be  added  in  excess  to  that  portion  which  has 
been  already  tested  with  sulphuric  acid. 

26.  The  presence  of  copper  may  be  confirmed  by  intro- 
ducing a  piece  of  clean  iron  or  steel  into  this  solution  mixed 
with  a  slight  excess  of  hydrochloric  acid  ;  a  red  coating  of 
metallic  copper  will  be  deposited  upon  the  metal. 

Ferrocyanide  of  potassium  may  be  added  to  the  original 
solution  ;  if  copper  is  present,  a  red-brown  precipitate  of 
ferrocyanide  of  copper  will  be  produced. 

27.  Metallic   Copper,   Cu,  is   identified  by  its  color,  its 
insolubility  in  diluted  hydrochloric  acid,  and  by  its  dissolv- 
ing rapidly  in  nitric  acid,  to  a  green  or  blue  solution  of 
nitrate  of  copper. 


COPPER    COMPOUNDS.  37 


COMMON  COMPOUNDS  OF  COPPER. 

Names.  Composition. 

Sulphate  of  copper,  or              )  Oxide  of  copper,  sulphuric  acid, 

Blue-stone                                   )  water. 

Arsenite  of  copper,  or               )  Oxide  of  copper,  arsenious  acid, 

Scheele's  green                            )  water. 

Basic  acetate  of  copper,  or        )  Oxide    of    copper,    acetic    acid, 

Verdigris                                       )  water. 

Basic  carbonate  of  copper,  or  )  Oxide  of  copper,  carbonic  acid, 

Malachite                                      )  water. 

Oxy  chloride  of  copper,  or         )  Oxide  of  copper,  chloride  of  cop- 

Brunswick  green                         )  per,  water. 

Copper,  oxygen. 


Sulphide  of  copper  Copper,  sulphur. 

Sulphate  of  Copper,  CuSO4,H2O,4Aq.,  forms  blue  dia- 
mond-shaped crystals,  often  grouped  into  irregular  masses. 
It  dissolves  easily  in  water,  yielding  a  blue  solution,  which 
is  copiously  precipitated  by  nitrate  or  chloride  of  barium. 
Dried  sulphate  of  copper  is  nearly  white,  and  becomes  blue 
when  moistened. 

Arsenite  of  Copper,  CuHAs03,  is  a  bright  green  powder, 
insoluble  in  water,  but  soluble  in  hydrochloric  acid  to  a 
green  liquid.  It  may  be  tested  for  arsenious  acid  according 
to  (33). 

Verdigris,  Cu2C2H3O2,CuO,6H2O,  has  a  bluish  green 
color.  It  is  partly  dissolved  by  water,  and  entirely  by  hy- 
drochloric acid,  to  a  green  solution.  When  heated  on  a 
knife  or  a  slip  of  glass,  it  is  blackened  and  emits  an  odor 
like  that  of  vinegar. 

The  Basic   Carbonates  of  Copper  are  blue  (2CuC03,Cu 
HaO2)  or  green  (CuCO3,CuH2O2),   insoluble  in  water,  but 
soluble,  with  effervescence,  in  hydrochloric  acid. 
4 


38  BISMUTH    CONFIRMED. 

Oxychloride  of  Copper,  Cu4Cl.2O3,4Aq.,  is  green.  It  is 
insoluble  in  water,  but  dissolves  in  acids.  Its  solution  in 
nitric  acid  may  be  tested  for  chlorine  with  nitrate  of  silver 
(Table  H). 

Cnpric  Oxide,  CuO,  is  a  black  powder,  insoluble  in  water, 
but  soluble  in  hydrochloric  acid,  on  boiling,  forming  a  green 
solution,  which  sometimes  becomes  turbid  when  mixed  with 
water,  from  the  separation  of  a  little  subchloride  of  copper. 

Cuprous  Oxide,  Cu2O,  is  red  or  red-brown;  it  is  not  dis- 
solved by  water,  but  hydrochloric  acid  dissolves  it,  on  boil- 
ing, to  a  brown  solution,  which  gives  a  thick  white  precipi- 
tate of  cuprous  chloride  (subchloride  of  copper)  when 
mixed  with  water.  Boiling  nitric  acid  dissolves  cuprous 
oxide,  forming  a  blue  solution  which  is  not  precipitated  by 
water. 

Sulphide  of  Copper,  Cu2S,  as  found  in  nature  (cuprous 
sulphide  or  copper-glance),  is  a  black  substance  with  a  some-,, 
what  metallic  lustre ;  insoluble  in  water  and  in  hydrochloric 
acid,  but  dissolved  by  boiling  in  nitric  acid  to  a  blue  solution, 
spongy  flakes  of  dark  colored  sulphur  usually  separating. 

The  artificial  sulphide  of  copper,  CuS,  is  usually  a  black 
powder  with  a  shade  of  green,  which  behaves  in  the  same 
way. 

28.  If  the  precipitate  of  oxide  of  bismuth,  Bi2O3,  pro- 
duced by  ammonia  be  small,  it  should  be  collected  upon  a 
filter,  washed  with  a  little  water  (1G),  and  very  carefully 
dissolved  by  dropping  two  or  three  drops  of  diluted  hydro- 
chloric acid  upon  it.  When  water  is  added  to  the  slightly 
acid  solution  of  chloride  of  bismuth  so  produced,  a  milky 
precipitate  of  oxychloride  of  bismuth  is  formed,  but  the 
presence  of  an  excess  of  acid  prevents  its  formation. 

To  confirm  the  presence  of  bismuth,  add  to  the  original 
solution  (or  to  the  solution  of  the  oxide  precipitated  by  am- 
inonia,  in  hydrochloric  acid,  even  after  dilution)  solution 
of  iodide  of  potassium;  this  will  produce  a  red  or  yellow 
color  if  bismuth  be  present  (or  even,  in  a  strong  solution,  a 


BISMUTH    COMPOUNDS.  39 

brown  precipitate  of  iodide  of  bismuth),  and  on  adding  a 
drop  of  acetate  or  nitrate  of  lead,  the  iodide  of  lead  which 
precipitates  will  have  a  brown  or  red  instead  of  its  usual 
yellow  color,  from  the  presence  of  iodide  of  bismuth.  If 
this  precipitate  be  dissolved  by  heating  the  liquid  and  add- 
ing a  few  drops  of  dil.  hydrochloric  or  acetic  acid,  it  will 
crystallize  out  in  very  beautiful  brown  or  red  scales  as  the 
solution  cools. 

An  excellent  confirmatory  test  for  bismuth  consists  in 
adding  to  the  original  solution  some  protochloride  of  tin 
(stannous  chloride,  prepared  by  boiling  a  fragment  of  tin 
with  strong  hydrochloric  acid)  and  an  excess  of  potash,  when 
a  black  precipitate  of  bismuthous  oxide,  BiO,  is  obtained. 
Should  the  stannous  chloride  produce  a  gray  or  white  pre- 
cipitate, becoming  dark  gray  on  adding  potash,  it  is  probably 
due  to  the  presence  of  mercury. 

29.  Metallic  Bismuth,  Bi,  is  a  brittle  metal  with  a  faint 
pink  reflection.  It  does  not  dissolve  in  hydrochloric  acid, 
but  dissolves  in  diluted  nitric  acid,  on  boiling. 

COMMON  COMPOUNDS  OF  BISMUTH. 

Names.  Composition. 

Basic  nitrate  of  bismuth,  or  )  Oxide  of  bismuth,  nitric  acid, 
Flake  white  $  water. 

Oxychloride  of  bismuth,  or  )  Oxide  of  bismuth,  chloride  of  bis- 
Pearl  white  )  muth,  water. 

Flake  white,*  Bi2N208.H20,  is  insoluble  in  water,  but 
dissolves  in  hydrochloric  acid.  When  heated  in  a  dry  glass 
tube  (17),  it  evolves  moisture,  which  condenses  in  drops 
on  the  cool  part  of  the  tube,  and  brown  vapors  of  nitric 
peroxide. 

Pearl  white,  B1OC1,  is  also  insoluble  in  water  and  soluble 

*  Flake  white  sometimes  consists  of  basic  carbonate  of  lead 
(white  lead). 


40  MERCURY    COMPOUNDS. 

in  hydrochloric  acid.     It  may  be  dissolved  in  nitric  acid,  and 
tested  for  chlorine  with  nitrate  of  silver  (Table  H). 

30.  In  order  to  be  quite  sure  of  the  presence  of  mercury 
in  a  solution,  it  must  be  boiled  with  metallic  copper.  If 
nitric  acid  be  present,  which  would  dissolve  the  copper,  it 
must  be  neutralized  by  adding  a  slight  excess  of  ammonia 
(5)  ;  enough  dilute  hydrochloric  acid  must  then  be  added  to 
destroy  the  odor  of  ammonia,  even  after  shaking,  and  two 
or  three  slips  of  bright  copper  introduced.  On  boiling,  the 
copper  will  acquire  a  bright  silvery  coating,  and  if  it  be 
rinsed  with  water,  dried  in  filter-paper  and  heated  in  a  dry 
tube  (17),  a  gray  crust  of  minute  globules  of  mercury  will 
be  formed  upon  the  side  of  the  tube,  uniting  into  larger 
globules  when  rubbed  with  a  glass  rod  or  a  wooden  match. 
Bismuth  also  deposits  upon  the  copper,  but  forms  a  dull  gray 
coating. 

When  mercury  is  present  in  the  form  of  cyanide  of  mer- 
cury, it  would  generally  escape  detection  until  the  boiling 
with  hydrochloric  acid  and  copper,  at  the  end  of  Table  C. 

31.  COMMON  MERCURIC*  COMPOUNDS. 

Na  mes.  Co?npositio  n  . 

Mercuric  chloride,  or  perchloride,  or 


Bichloride  of  mercury,  or  Mercury,  chlorine. 

Corrosive  sublimate 


Mercuric  sulphide,  or  ) 

Vermilion,  or  cinnabar  $ 


Mercurv   snlnhnr 
my'  Sulphl 


Mercuric  oxide,  or  )  ,, 

Nitric  oxide  of  mercury  \  Mercury,  oxygen. 

White  precipitate  \  Mercury,  chlorine,  nitro- 

£          gen,  hydrogen. 

Mercuric  iodide  Mercury,  iodine. 


Mercuric  cyanide 


Mercury,   cyanogen   (car- 
bon, and  nitrogen). 


*  Nitric  acid  converts  mercurous  compounds  into  mercuric  com- 
pounds ;  hence,  if  this  acid  should  have  been  used  to  dissolve  the 
original  substance,  the  latter  may  possibly  have  been  a  mercurous 


MERCURY    COMPOUNDS.  41 

Corrosive  Sublimate,  HgCl2,  is  sold  either  in  shining  white 
semi-transparent  masses  or  as  a  white  crystalline  powder.  It 
dissolves  readily  when  boiled  with  water,  and  crystallizes 
from  a  strong  solution  in  white  needles.  When  heated  in  a 
small  tube  (17),  it  melts  very  easily  to  a  perfectly  clear 
liquid,  which  crystallizes  in  fine  needles  on  cooling.  By 
continuing  the  heat,  it  is  boiled  away  in  vapor  which  has  a 
fearfully  suffocating  effect  upon  the  nose. 

Vermilion,  HgS,  is  known  by  its  bright  red  color.  It  is 
insoluble  in  water,  and  in  hydrochloric  or  nitric  acid  sepa- 
rately, but  it  dissolves  in  a  mixture  of  the  two  acids,  with 
separation  of  spongy  flakes  of  sulphur. 

Cinnabar,  HgS,  the  chief  ore  of  mercury,  is  generally  met 
with  in  dark  brown  very  heavy  hard  masses,  which  become 
red  when  scraped  with  a  knife.  In  its  relation  to  solvents 
it  resembles  vermilion. 

Nitric  Oxide  of  Mercury,  HgO,  is  a  bright  red  shining 
powder,  insoluble  in  water,  but  soluble  in  hydrochloric  acid. 

White  Precipitate,  HgClNH2,  is  a  heavy  white  earthy- 
looking  substance,  insoluble  in  watec,  but  soluble  in  hydro- 
chloric acid.  When  boiled  for  some  time  with  water,  it 
becomes  yellow.  On  boiling  it  with  potash,  it  evolves  the 
odor  of  ammonia. 

Mercuric  Iodide,  or  Biniodide  of  Mercury,  HgI2,  is  a 
scarlet  powder,  insoluble  in  water,  but  dissolved  by  boiling 
hydrochloric  acid.  When  heated  on  a  slip  of  glass,  it  be- 
comes bright  yellow,  and  passes  off  in  yellow  fumes.  The 
yellow  powder  becomes  red  when  rubbed  with  a  glass  rod. 

Mercuric  Cyanide,  or  Cyanide  or  Bicyanide  of  Mercury, 
Hg2CN,  forms  white  prismatic  crystals  which  dissolve  in 
boiling  water.  When  heated  in  a  dry  tube  (17)  they 
crackle,  melt,  and  evolve  cyanogen,  which  may  be  recog- 
nized by  its  odor  and  by  its  burning  with  a  pink  flame.  A 
brown  residue  is  left  at  the  bottom  of  the  tube,  and  the 
cooler  part  of  the  tube  is  covered  with  a  gray  deposit  of  mer- 
cury which  unites  into  globules  when  rubbed  with  a  match. 


42         REINSCIl'S    AND    MAKSIl's    TESTS    FOR    ARSENIC. 

32.  The  carbonate  of  ammonia  is  to  be  added  in  excess, 
so  that  the  smell  of  ammonia  is  quite  perceptible  on  warming 
the  liquid  ;  otherwise  the  sulphide  of  arsenic  would  not  be 
dissolved  and  might  be  mistaken  for  that  of  tin. 

It  is  better  to  collect  a  little  of  the  precipitate  upon  a  filter, 
to  wash  it  once  or  twice  with  water  (16),  and  to  pour  some 
warm  carbonate  of  ammonia  over  it.  If  there  be  any  doubt 
whether  the  precipitate  has  been  dissolved,  test  a  little  of  the 
solution  in  carbonate  of  ammonia  with  excess  of  hydrochloric 
acid,  when  sulphide  of  arsenic  will  be  separated  in  yellow 
flakes. 

33.  Should  any  confirmatory  test  be  required  for  arsenic, 
either  Reinsch's  test  or  Marsh's  test  may  be  employed. 

fieinsch's  test  for  arsenic Boil  a  little  of  the  original 

substance  with  excess  of  hydrochloric  acid  and  a  few  strips 
of  bright  copper  for  a  minute  or  two.     The  copper  displaces 
the  arsenic  from  the  solution,  and  a  dark  gray  compound 
of  arsenic  with  copper  is  formed  upon  the  surface  of  the 
strips.     Rinse  these  with  a  little  water,  dry  them  on  filter- 
paper,  and  heat  them  gently  in  a 
small  tube  closed  at  one  end  (17)  ; 
minute  shining  crystals  of  arsen- 
ious    acid    will    be    deposited    on 
the  cool  part  of  the  tube,  having 
been  produced  by  the  combination 
of  the  arsenic  with  oxygen  from 
the  air.     If  the  crystalline  deposit 
is  examined  with  the  microscope 
(for  which  purpose  the  binocular 
is  to  be  preferred),  it  will  be  seen 
to  consist  of  octahedral  crystals  (fig.  17). 

34.  Marsh's  test  for  arsenic. — Dissolve  the  substance,  if 
possible,  in  water  or  hydrochloric  acid.     If  it  be  insoluble  in 
these,  dissolve  it  in  nitric  acid,  evaporate  the  solution  to  dry- 
ness  in  a  small  dish,  and  redissolve  the  residue  in  water  with 

o    littlo    Kir/lr/wtliWif    on^rl 


MARSH'S  TEST  FOR  ARSENIC. 


43 


Arrange  an  apparatus  as  represented  in 
fig.  18  ;  the  funnel-tube  A,  and  the  bent 
tube  (229)  B,  being  passed  through  air-tight 
perforated  corks  (228).  B  has  been  drawn 
out  to  a  moderately  fine  jet  by  softening  it 
in  the  blowpipe  flame  (fig.  15),  drawing  it 
out  to  a  narrow  neck  (fig.  19),  and  cutting 
this  across  with  a  file,  at  a. 

FIG.  19. 


FIG.  18. 


Introduce  into  the  bottle  enough  granulated  zinc*  to  cover 
the  bottom,  fill  the  bottle  about  one-third  with  water,  and 
pour  in  dilute  sulphuric  acid,  through  the  funnel-tube  (the 
lower  end  of  which  must  dip  beneath  the  water)  until  mode- 
rate effervescence,  from  the  evolution  of  hydrogen  gas,  takes 
place.  Keep  the  tube  as  far  away  from  a  flame,  because  the 
bottle  is  now  filled  with  an  explosive  mixture  of  hydrogen 
and  air.  Incline  the  gas-bottle  and  hold  a  small  test-tube 
over  the  tube  ft,  as  represented  in  fig.  20,  for  about  a  minute, 
slowly  withdraw  it,  keeping  its  mouth  downwards,  and  apply 
it  .to  a  flame  ;  if  it  explodes,  the  hydrogen  in  the  bottle  is  still 

FIG.  20. 


FIG.  21. 


*  To  granulate  zinc,  melt  it  in   an   iron  ladle,  stand  upon   the 


44  ARSENIC    IDENTIFIED. 

mixed  with  air,  and  it  would  explode  if  lighted.  Repeat  the 
experiment  until  the  hydrogen  can  be  seen  to  burn  steadily 
away  in  the  test-tube.  The  hydrogen  issuing  from  the  tube 
B  may  then  be  kindled  with  safety.  Hold  the  lid  of  a  porce- 
lain crucible  in  the  flame  (fig.  21),  pressing  it  close  up  to 
the  jet.  No  spot  (of  arsenic  or  antimony)  will  be  deposited 
upon  the  porcelain  if  the  hydrogen  be  pure. 

Pour  a  few  drops  of  the  solution  to  be  tested  for  arsenic, 
prepare  as  directed  above,  into  the  funnel-tube  A,  and  re- 
peat the  experiment  with  the  porcelain  lid.  If  arsenic  be 
present,  arsenietted  hydrogen  will  be  formed,  and  will  de- 
posit a  dark  brown  stain  of  arsenic  on  the  porcelain  surface. 
Make  a  stain  upon  another  lid  in  the  same  way. 

Heat  the  tube   B  with  a  spirit-lamp 
FIG.  22.  (fjge  22)  for  a  minute  or  two,  when  the 

arsenietted  hydrogen  will  be  decom- 
posed, and  a  nearly  black  shining  crust 
of  arsenic  will  be  deposited  on  the  cooler 
part  of  the  tube. 

To  prove  that  these  results  are   due 
to  arsenic,  and  not  to  antimony,  which 
might  imitate  them,  touch  one  of  the 
stains  with  a  glass  rod  dipped  in  solu- 
tion   of  chloride    of  lime,  which  will  dissolve   a   stain   of 
arsenic,  but  not  that  of  antimony. 

Test  the  other  stain  in  the  same  way  with  yellow  hydro- 
sulphate  of  ammonia,  which  will  not  dissolve  a  stain  of 
arsenic,  but  dissolves  that  of  antimony.  If  the  deposit  formed 
in  B  were  due  to  antimony,  it  would  be  produced  close  to  the 
hot  part  of  the  tube,  whilst  the  arsenical  crust  is  deposited 
upon  the  cooler  part  of  the  tube.  To  be  quite  sure  of  its 
character,  make  a  deep  file-mark  at  each  end  of  it,  and  break 
off  the  end  of  the  glass.  Wrap  the  piece  containing  the 
deposit  in  a  piece  of  stout  paper,  break  it  into  fragments 
(not  into  powder),  and  heat  one  or  two  of  these  in  a  small 
tube  (17),  when  the  arsenic  will  be  oxidized,  and  a  shining 


ARSENICAL    COMPOUNDS.  45 

ring  of  crystals  of  arsenious  acid  will  be  deposited  on   the 
cooler  part  of  the  tube. 

35.  Metallic  Arsenic,  As,  is  a  dark  gray  brittle  substance, 
with  metallic  lustre.  It  is  insoluble  in  water  and  in  hydro- 
chloric acid,  but  dissolves  in  boiling  nitric  acid.  When 
heated  in  air,  it  emits  a  smell  of  garlic.  Heated  in  a  dry 
tube  (17)  it  is  converted  into  vapor,  which  condenses  higher 
up  the  tube,  partly  as  a  black  shining  crust,  partly  as  a 
white  crystalline  powder  of  arsenious  acid  produced  by  the 
oxygen  of  the  air  in  the  tube. 


COMMON  COMPOUNDS  OF  ARSENIC. 

Names.  Composition. 


Arsenite  of  copper,  or  ?  A         •  -j        -j      * 

Scheele's  green  \  Arsenious  acid,  oxide  of  copper. 

Arsenic  acid  Arsenic,  oxygen. 

Arseniate  of  soda  Arsenic  acid,  soda,  water. 

Tersulpliide  of  arsenic,  or  )  A          .          ,   , 

Yellow  orpiment  j  Arsemc'  sulPlmr' 


Bisulphide  of  arsenic,  or 
Realgar  or  red  orpiment 


A          . 
Arsemc> 


Iodide  of  Arsenic  Arsenic,  iodine. 

Arsenious  Acid,  As203,  is  sold  either  in  opaque  porcelain- 
like  masses,  or  as  a  white  powder.  It  seems  insoluble  in 
water,  unless  long  boiled  with  it,  but  dissolves  in  boiling 
hydrochloric  acid,  and  more  readily  in  boiling  nitric  acid, 
evolving  from  the  latter  brown  fumes  of  nitrous  acid. 

When  a  little  arsenious  acid  is  heated  in  a  dry  tube  (17), 
it  is  entirely  converted  into  vapor,  and  is  deposited  on  the 
cooler  part  of  the  tube  as  a  white  crystalline  powder  (24G, 
251). 

Arsenite  of  Copper  has  been  described  at  page  37.    When 


46  AUSENICAL    COMPOUNDS. 

heated  in  a  dry  tube  (17),  it  evolves  vapor  of  arsenious  acid 
Avhich  condenses  to  a  crystalline  powder. 

Arsenic  Acid,  As2O5,  is  commonly  sold  in  combination 
with  water,  as  hydrated  arsenic  acid,  in  white  irregular  lumps, 
which  soon  become  damp  by  absorbing  water  from  the  air. 
It  dissolves  in  water,  and  if  the  solution  be  mixed  with 
hydrochloric  acid,  and  a  considerable  volume  of  hydro- 
sulphuric  acid  added,  it  is  not  precipitated  in  the  cold,  but 
when  boiled  it  yields  a  white  precipitate  of  sulphur,  followed 
by  a  yellow  precipitate  of  tersulphide  of  arsenic. 

Arseniate  of  soda,  Na,HAsO4.7Aq.,  forms  prismatic  crys- 
tals which  dissolve  easily  in  water,  yielding  a  solution  which 
is  alkaline  to  test-papers  (18),  and  behaves  like  arsenic  acid 
with  hydrochloric  and  hydrosulphuric  acids. 

The  solution  of  arseniate  of  soda  gives  a  red-brown  pre- 
cipitate with  nitrate  of  silver,  and  the  solution  of  arsenic  acid 
will  give  the  same  precipitate  if  ammonia  be  very  cautiously 
added  after  the  nitrate  of  silver. 

Tersulphide  of  Arsenic,  As2S3,  is  bright  yellow,  insoluble 
in  water  and  in  hydrochloric  acid,  but  dissolved  by  boiling 
nitric  acid,  with  separation  of  sulphur.  It  dissolves  in  warm 
ammonia,  or  potash,  yielding  a  colorless  s6lution,  from  which 
it  is  reprecipitated  in  yellow  flakes  by  an  excess  of  hydro- 
chloric acid. 

Realgar,  As2S2,  is  sold  in  orange-red  masses  or  powder. 
It  behaves  like  the  preceding  with  water  and  acids,  but  is  not 
entirely  dissolved  by  potash,  leaving  a  dark  brown  residue. 

Iodide  of  Arsenic,  AsI3,  forms  brick-red  flakes  which  are 
dissolved  to  a  considerable  extent  by  boiling  water,  and 
evolve  violet  vapors  when  boiled  with  nitric  acid. 

36.  If  too  little  carbonate  of  ammonia  be  added,  the 
sulphide  of  arsenic  may  be  mistaken  for  bisulphide  of  tin. 
On  adding  ammonia,  the  sulphide  of  arsenic  dissolves  very 
readily,  but  the  bisulphide  of  tin  dissolves  with  difficulty. 

To  confirm  the  presence  of  tin,  place  in  a  little  of  the 
original  solution  (which  should  contain  free  hydrochloric  but 


TIN    COMPOUNDS.  47 

not  nitric  acid)  a  piece  of  zinc ;  after  a  short  time  metallic 
tin  will  be  deposited  as  a  spongy  mass;  rinse  this  with  water, 
boil  it  with  a  little  hydrochloric  acid  to  dissolve  it  in  the 
form  of  chloride  of  tin  (stannous  chloride),  and  test  it  with 
perchloride  of  mercury  (22). 

If  the  original  solution  contains  nitric  acid,  add  ammonia 
in  slight  excess  to  neutralize  it,  and  acidify  the  solution  again 
with  hydrochloric  acid  before  testing  with  zinc. 

37.  The  mode  of  identifying  metallic  tin  has  been  de- 
scribed at  (23). 

COMMON  STANNIC  COMPOUNDS  (OR  PERSALTS  OF  TIN.)* 

Names.  Composition. 

Binoxide  of  tin,  or       )      m. 

Stannic  acid  )      Tin,  oxygen. 

Stannate  of  soda  Stannic  acid,  soda,  water. 

Bisulphide  of  tin          )      m. 

Aurum  musivum  Tin>  sulphur. 


Stannic  chloride,  or     ) 

Nitromuriate  of  tin     f      Tm'  chlorine  (water). 

Stannic  chloride. 
Hydrochlorate  of  ammonia. 


Pink  salt  |      Stannic  chloride. 


Binoxide  of  Tin,  SnO2,  is  insoluble  in  water  and  acids 
and  will,  therefore,  not  be  considered  at  present. 

Stannate  of  Soda,  Na2SnO3.4Aq.,  is  usually  sold  in  opaque 
irregular  crystals,  which  are  soluble  in  cold  water,  though 
generally  leaving  a  white  residue.  The  solution  is  alkaline 
(18).  Hydrochloric  acid  added  drop  by  drop  causes  a  white 
precipitate  of  stannic  acid,  which  is  redissolved  by  an  excess 
of  the  acid. 

Bisulphide  of  Tin,  SnS2,  or  bronze   powder,  or  Mosaic 

*  Nitric  acid  converts  stannous  compounds  into  stannic  com- 
pounds ;  hence,  if  this  acid  has  been  used  to  dissolve  the  original 
substance,  this  may  have  been  a  stannous  compound  (23). 


48  TIN    COMPOUNDS. 

gold,  is  a  golden  yellow,  scaly  substance,  insoluble  in  water, 
in  hydrochloric  acid,  and  in  nitric  acid,  but  dissolved  by 
boiling  with  hydochloric  acid  and  adding  a  little  nitric  acid. 
Much  nitric  acid  causes  the  separation  of  white  binoxide  of 
tin. 

Stannic  Chloride,  SnCl4,  is  commonly  met  with  in  the 
state  of  solution,  which  is  highly  acid  to  test-papers  (18). 
It  may  be  tested  for  chlorine  with  nitrate  of  silver  (Table  H). 

Pink  Salt,  SnCl4.2NH4Cl,  may  be  tested  for  chlorine  in 
a  similar  manner.  When  heated  with  potash  it  evolves 
ammonia. 

38.  The  presence    of   antimony  may  be    confirmed    by 
acidifying  the  original  solution  with  hydrochloric  acid,  and 
introducing  a  piece  of  zinc,  when  a  sooty  black  powder  of 
metallic  antimony  will  be  deposited. 

Or  a  few  drops  of  the  solution  (free  from  nitric  acid) 
acidified  with  hydrochloric  acid,  may  be  placed  upon  a 
surface  of  platinum  (foil)  and  a  piece  of  zinc  made  to  touch 
the  platinum  ;  a  dark  stain  of  antimony  will  be  formed  upon 
the  latter  metal.  If  this  stain  be  rinsed  with  water,  and 
wetted  with  yellow  hydrosulphate  of  ammonia,  it  will  be 
dissolved  on  warming,  and  the  solution,  if  evaporated  on  the 
platinum,  will  deposit  the  orange-colored  sulphide  of  anti- 
mony. 

Or  the  solution,  containing  hydrochloric  acid  only,  and  not 
nitric  acid,  may  be  tested  by  Marsh's  test  (34). 

Or  a  little  of  the  original  substance  may  be  boiled  with 
excess  of  hydrochloric  acid,  and  a  few  strips  of  copper,  when 
the  latter  will  displace  the  antimony  and  become  covered 
with  a  purple  antimonial  film. 

39.  Metallic  Antimony,  Sb,  is  known  by  its  great  brittle- 
ness  and  brilliant  lustre.     It  is  not  attacked  by  water,  and  to 
a  slight  extent  only  by  boiling  hydrochloric  acid.     When 
boiled  with  diluted  nitric  acid,  it  is  converted,  though  slowly, 
into   a  white    powder  (antimonic    acid)  which    is    slightly 
soluble  in  the  nitric  acid.     A  mixture  of  hydrochloric  acid 


ANTIMONY    COMPOUNDS.  49 

with  a  little  nitric  acid  dissolves  the  metal,  and  if  a  large 
excess  of  acid  be  avoided,  the  addition  of  a  large  volume  of 
water  to  the  solution  causes  a  thick  white  precipitate  of  oxy- 
chloride  of  antimony. 

COMMON  COMPOUNDS  OF  ANTIMONY. 

Names.  Composition. 

Tersulphide  of  antimony,  or     ) 

Crude  antimony  ore  ]      Antimony,  sulphur. 

Teroxide  of  antimony  )        ... 

Flowers  of  antimony  }      Antimony,  oxygen. 

Tartar  emetic  -J      Teroxide  of  antimony. 

I      Potash,  tartaric  acid,  water. 

Terchloride  of  antimony  Antimony,  chlorine. 

Antimoniate  of  potash  Aiitimonic  acid,  potash. 

Tersulphide  of  Antimony,  Sb2S3,  as  found  in  nature,  is  a 
dark  gray  crystalline  substance  with  decidedly  metallic 
lustre.  It  is  unaffected  by  water,  but  boiling  hydrochloric 
acid  dissolves  it  slowly,  evolving  the. odor  of  hydrosulphuric 
acid.  If  the  solution  thus  obtained  be  filtered  and  mixed 
with  water,  it  generally  gives  an  orange-red  precipitate.  A 
mixture  of  hydrochloric  acid  with  a  little  nitric  acid  dis- 
solves it  readily,  flakes  of  sulphur  being  separated. 

The  artificial  tersulphide  of  antimony,  or  antimony-ver- 
milion, is  an  orange  red  powder,  which  behaves  with  acids 
like  the  native  tersulphide. 

Teroxide  of  Antimony,  Sb2O3,  is  a  grayish-white  powder, 
insoluble  in  water,  but  dissolved  by  hydrochloric  acid.  When 
heated  on  a  knife  or  a  slip  of  glass,  it  becomes  yellow,  but 
turns  white  again  on  cooling. 

Tartar-emetic  2(K.SbO.C4H4O6).Aq.,  forms    hard  white 

crystals,  or  a  white  powder,  readily  dissolved  by  hot  water. 

The  solution  gives  a  white  precipitate  of  teroxide  of  antimony 

on  adding  a  drop  of  diluted  hydrochloric  acid,  but  an  excess 

5 


50  ANTIMONY    COMPOUNDS. 

of  acid  readily  dissolves  it.  When  tartar-emetic  is  heated 
on  a  knife  or  a  slip  of  glass  it  is  carbonized,  and  evolves  the 
peculiar  odor  of  burnt  sugar,  which  characterizes  the  pro- 
ducts of  decomposition  of  tartaric  acid. 

Terchloride  of  Antimony,  SbCl3,  in  the  pure  state  forms  a 
soft  gray  fusible  solid,  but  it  is  commonly  met  with  in  the 
state  of  solution,  usually  of  a  yellow  color,  due  to  the  pres- 
ence of  iron.  When  largely  diluted  with  water,  it  gives  a 
white  precipitate  of  oxychloride  of  antimony. 

Antimoniate  of  Potash,  KSbO3,  is  usually  sold  as  a  white 
powder,  which  is  partly  dissolved  by  boiling  water,  yielding 
an  alkaline  solution  (18).  If  this  solution  be  filtered,  and  a 
drop  of  diluted  hydrochloric  acid  added  to  it,  it  yields  a  slight 
white  precipitate  of  antimonic  acid,  which  dissolves  in  an 
excess  of  the  acid.  If  a  drop  of  the  aqueous  solution  be 
briskly  stirred,  on  a  slip  of  glass,  with  a  drop  of  solution  of 
carbonate  of  soda,  it  gives  a  precipitate  (antimoniate  of  soda) 
which  deposits  on  the  lines  where  the  rod  has  rubbed  against 
the  glass. 

40.  Examples  for  Practice  in  Tables  13  and  O. — The 
following  substances  may  be  selected  (10)  : — 


Corrosive  sublimate, 
Acetate  of  lead, 
Sulphate  of  copper, 
Oxychloride  of  bismuth, 
Chloride  of  lead, 


Arsenious  acid, 
Litharge, 
Red  lead, 
Oxide  of  copper, 
Metallic  tin. 


TABLE    D. 


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52  IRON    IDENTIFIED. 

NOTES  TO  TABLE  D. 

42.  When  time  permits,  it  is  desirable  to  collect  a  little 
of  the  precipitate  upon  a  filter  (4),  and  to  wash  it  (16)  be- 
fore treating  it  with  hydrochloric  acid,  which  may  be  poured 
over  it  upon  the  filter. 

43.  A  white  or  gray  residue  of  sulphur,  derived  from  the 
sulphide  of  ammonium,  is  often  left  undissolved,  especially  if 
the    precipitate  be  treated  w'ith  hydrochloric  acid  without 
being  washed. 

44.  To  ascertain  whether  the  iron  is  present  as  a  ferrous 
or  as  a  ferric  salt,  test  the  original  solution,  which  should  be 
acid  (18),  with  ferrocyanide  of  potassium. 

Ferric  salts  give,  with  ferrocyanide  of  potassium,  a  dark 
blue  precipitate  of  ferrocyanide  of  iron  (Prussian  blue);  and 
with  ferridcyanide  of  potassium,  a  dark  brown  solution,  but 
no  precipitate. 

Ferrous  salts  give,  with  ferrocyanide  of  potassium,  a  lighter 
blue  precipitate  of  the  double  ferrocyanide  of  iron  and  potas- 
sium; and  with  ferridcyanide  of  potassium,  a  dark  blue  pre- 
cipitate of  Turnbull's  blue. 

Potash,  added  in  excess,  produces  a  brown  precipitate  in 
solutions  of  ferric  salts,  and  a  dingy  green  precipitate  in 
those  of  ferrous  salts;  this  precipitate  slowly  becomes  brown 
when  exposed  to  the  air,  from  which  it  absorbs  oxygen. 

Since  nitric  acid  converts  ferrous  into  ferric  salts,  no  con- 
clusion as  to  the  state  of  the  iron  can  be  drawn  from  these 
tests  when  that  acid  has  been  employed  in  dissolving  the 
substance. 

45.  Metallic  Iron,  Fe,  would  generally  be  recognized  by 
its  external  appearance.     It  dissolves  slowly  in  dilute  hydro- 
chloric acid,  evolving  a  disagreeable  smell  of  impure  hydro- 
gen, quite  different  from  that  of  hydrosulphuric  acid  (see 
Sulphide  of  Iron,  p.  55).     Ammonia  added  in  excess  (5)  to 
this  solution,  gives  a  dingy  green  precipitate  which  gradually 


VARIETIES    OF    IRON    DISTINGUISHED.  53 

Wrought  Iron  (malleable  or  bar  iron)  may  be  identified 
by  warming  two  or  three  grains  of  it  with  diluted  nitric  acid 
(specific  gravity  1.2*)  when  it  will  dissolve  entirely,  yield- 
ing a  solution  which  is  nearly  colorless  after  cooling,  pro- 
vided that  the  nitric  acid  be  free  from  chlorine. 

Steel,  when  tested  in  this  way,  gives  a  solution  which  re- 
tains a  brown-yellow  color  after  cooling,  due  to  the  products 
of  the  action  of  nitric  acid  upon  the  combination  of  iron  with 
carbon,  which  is  present  in  steel. 

White  Cast  Iron,  heated  with  nitric  acid  of  the  above 
strength,  also  dissolves,  leaving  little  or  no  black  residue  of 
uncombined  carbon,  but  the  solution  has  usually  a  darker 
color  than  that  furnished  by  steel,  because  white  iron  com- 
monly contains  a  larger  proportion  of  carbon  in  combination 
with  the  metal. 

Gray  Cast  Iron  (ordinary  pig  iron)  leaves  a  considerable 
black  residue  of  graphite  (uncombined  carbon)  when  heated 
with  nitric  acid,  and  if  this  be  filtered  off  or  allowed  to  sub- 
side, the  liquid  will  usually  have  a  pale  brown-yellow  color, 
produced  by  a  little  combined  carban. 

Mottled  Cast  Iron  furnishes  a  result  intermediate  between 
those  obtained  with  white  and  gray  cast  irons,  the  color  of 
the  solution  being  paler  than  in  the  former  case,  and  the 
black  residue  less  abundant  than  in  the  latter. 

For  the  common  compounds  of  Iron,  see  next  page. 

*  Three  measures  of  ordinary  strong  nitric  acid  mixed  with  four 
measures  of  water. 


54  IRON  COMPOUNDS. 

COMMON  COMPOUNDS  OF  IRON. 

Names.  Composition. 

Iron> 


Magnetic  oxide  of  iron,  or  1  Iron,  oxygen. 

Ferroso-ferric  oxide  ) 

Sulphate  of  iron,  or  |  f  Oxide  of  iron,  sulphuric  acid, 

Ferrous  sulphate  )  \  Water. 


Bisulphide  of  iron,  )  T 

Iron  pyrites  )  Iroll>  slllPhur- 

Sp""onor'°r  }  Oxide  of  iron,  carbonic  acid. 

Perchloride  or  sesquichloride  of  iron  Iron,  chlorine. 

Ferrocyanide  of  iron,  or  |  Iron,  cyanogen  (carbon  and 

Prussian  blue  )           nitrogen). 

Iodide  of  iron  Iron,  iodine. 


of  iron>  silicic  acid« 


Sesquioxide  of  Iron,  Fe2O3,  or  ferric  oxide,  is  met  with  in 
several  forms. 

Red  Hcematite  Ore,  or  natural  sesquioxide  of  iron,  is  a 
hard  compact  mineral  of  a  dark  reddish-brown  color,  not 
easily  reduced  to  a  powder,  which  is  dark  red.  It  is  not 
dissolved  by  water,  but  hydrochloric  acid  slowly  dissolves  it, 
yielding  a  yellow  solution,  which  gives  a  rust-colored  pre- 
cipitate with  ammonia. 

Specular  Iron  Ore,  another  natural  variety  of  the  sesqui- 
oxide, is  black,  and  has  a  brilliant  lustre.  Its  relations  to 
solvents  resemble  those  of  haematite. 

Brown  Haematite  Ore  contains  water  in  combination  with 
ferric  oxide,  and  will  therefore  give  off  steam  when  heated  in 
a  dry  tube  (17).  It  varies  in  color  through  different  shades 
of  yellow,  brown,  and  red.  Hydrochloric  acid  dissolves  it 
more  rapidly  than  it  does  the  two  preceding  ores. 


IRON    COMPOUNDS.  OO 

The  artificial  sesquioxide  of  iron,  which  is  commonly 
known  as  Colcothar,  Crocus,  or  Jewellers'  Rouge,  has  a 
brighter  red  color  than  haematite,  which  it  resembles  in  its 
behavior  with  hydrochloric  acid. 

Rust  has  the  same  characters  as  brown  haematite. 

Magnetic  or  Black  Oxide  of  Iron,  Fe3O4,  as  found  in 
nature,  is  a  hard  mineral  with  considerable  lustre.  Hydro- 
chloric acid  slowly  dissolves  it,  with  the  aid  of  heat,  yielding 
a  greenish  solution  which  gives  a  dingy  green  precipitate  on 
addition  of  ammonia.  The  black  oxide  of  iron  which  com- 
poses forge  scales  possesses  similar  characters,  but  is  usually 
devoid  of  lustre. 

Sulphate  of  Iron  (copperas,  green  vitriol,  FeSO4.H2O.6Aq.), 
forms  transparent  green  crystals,  often  streaked  with  rusty 
brown.  It  dissolves  when  shaken  with  cold  water,  but  when 
boiled  with  water,  it  generally  deposits  a  brown  basic  per- 
sulphate of  iron  formed  by  the  decomposition  of  some  ferric 
sulphate  contained  in  the  salt.  This  deposit  is  easily  dissolved 
by  hydrochloric  acid,  forming  a  yellow  solution. 

Dried  Sulphate  of  Iron,  FeS04,  is  a  brownish-white  pow- 
der which  is  not  easily  dissolved  by  cold  water,  and  behaves 
like  the  green  sulphate  when  boiled.  Hydrochloric  acid 
readily  dissolves  it. 

Sulphide  of  Iron,  FeS,  is  a  black  substance  somewhat 
resembling  iron  itself,  insoluble  in  water,  but  dissolving  in 
hydrochloric  acid,  and  evolving  a  powerful  offensive  odor  of 
hydrosulphuric  acid.  On  adding  ammonia  to  this  solution 
before  the  hydrosulphuric  acid  is  boiled  off,  a  black  precipi- 
tate of  sulphide  of  iron  is  obtained. 

Iron  pyrites,  FeS2,  has  the  color  and  lustre  of  pale  brass. 
It  often  occurs  in  distinct  cubical  crystals,  but  more  com- 
monly in  rounded  lumps  which  are  dark  brown  externally, 
and  have  a  radiated  crystalline  structure  when  broken.  It  is 
not  attacked  by  water  or  hydrochloric  acid,  but  nitric  acid 
dissolves  it  on  boiling,  with  separation  of  flakes  of  sulphur 
and  formn.Hon  of  siilnhnrip.  Moid,  whip.li  mn.v  hp  Ht*ts*t*ts*f\  K^r 


56  IRON    COMPOUNDS. 

Spathic  Iron  Ore,  FeCO3,  or  ferrous  carbonate,  varies  very 
much  in  appearance,  but  usually  forms  grayish-white  masses 
which  seem  to  be  made  up  of  tabular  crystals.  It  is  unaffected 
by  water,  but  dissolves  in  hydrochloric  acid,  assisted  by  heat, 
with  effervescence  caused  by  the  escape  of  carbonic  acid. 

The  red  carbonate  of  iron  of  the  druggist  is  chiefly  sesqui- 
oxide  of  iron. 

Per  chloride  of  Iron,  or  muriate  of  iron,  or  ferric  chloride, 
Fe2Cl6,  is  only  met  with  in  solution,  which  has  a  yellow  or 
red  color,  and  gives  a  rust-colored  precipitate  with  ammonia. 
The  chlorine  may  be  detected  in  it  by  nitrate  of  silver  (Table 
H).  The  tincture  of  sesquichloride  of  iron  is  known  by  its 
alcoholic  smell. 

Prussian  Blue,  Fe5C]2Nla,  is. insoluble  in  water  and  in  the 
diluted  acids.  It  may  be  known  by  its  becoming  brown 
when  boiled  with  potash;  if  the  solution  of  ferrocyanide  of 
potassium  thus  obtained  be  filtered  from  the  deposited  per- 
oxide of  iron,  and  mixed  with  excess  of  hydrochloric  acid,  it 
will  give  a  blue  precipitate  on  adding  perchloride  of  iron. 
Concentrated  hydrochloric  acid  dissolves  Prussian  blue,  on 
boiling,  giving  a  yellow  solution,  from  which  the  Prussian 
blue  is  precipitated  by  much  water. 

Iodide  of  Iron  or  ferrous  iodide,  FeI2,  is  commonly  sold 
in  solution,  often  mixed  with  syrup  to  preserve  it.  Solution 
of  iodide  of  iron  has  a  very  pale-green  color,  but,  if  partly 
oxidized,  it  is  rusty  brown  and  opaque.  It  may  be  tested 
for  iodine  according  to  Table  H.  The  solid  iodide  forms 
brownish-green  lumps  which  are  deliquescent  and  have  a 
crystalline  fracture. 

The  Iron  Slags,  or  silicates  of  iron,  obtained  in  the  pro- 
cesses of  refining  and  puddling  cast  iron,  are  black  and  pos- 
sessed of  considerable  lustre.  They  are  unaffected  by  water, 
but  if  finely  powdered  and  boiled  with  hydrochloric  acid 
(especially  if  the  acid  be  concentrated),  they  partly  dissolve, 
emitting  an  odor  of  hydrosulphuric  acid  (caused  by  the  pre- 


COr.ALT    AND    ITS    COMPOUNDS.  57 

46.  It  is  desirable  to  confirm  the  indication  of  Cobalt 
either  by  the  blowpipe  (268),  or  by  collecting  this  precipitate 
upon  a  filter  (4),  washing  it  (1G)  and   dissolving  it  off  the 
filter  with  a   little   dilute  hydrochloric  acid.     The  solution 
thus  obtained  should  have  a  light  pink  color,  and  if  a  little 
of  it  be  dropped  upon  filter-paper,  the  latter  should  become 
blue  or  green  when  gently  warmed.    Ferridcyanide  of  potas- 
sium added  to  the  solution   should  give  a  purple-brown  pre- 
cipitate. 

47.  Neither  metallic  cobalt,  Co,  nor  its  compounds  are 
frequently  met  with.     The  metal  bears  considerable  resem- 
blance to  iron. 

Cobalt- glance,  one  of  its  chief  ores,  composed  of  cobalt, 
arsenic,  and  sulphur,  CoS2.CoAs2,  is  a  black  lustrous  mineral, 
soluble  in  boiling  nitric  acid,  yielding  a  pink  solution,  and 
depositing  flakes  of  sulphur. 

Commercial  Oxide  of  Cobalt,  CoO,  is  a  bluish-gray,  brown 
or  black  powder,  according  to  the  mode  of  preparing  it. 
Hydrochloric  acid  dissolves  it  to  a  green  or  blue  liquid  which 
becomes  pink  when  diluted. 

Smalt  is  glass  which  lias  been  colored  with  cobalt  and 
powdered.  It  is  insoluble  in  water,  hydrochloric  and  nitric 
acids. 

Nitrate  of  Cobalt,  Co2NO3.6Aq.,  is  a  red  salt,  very 
soluble  in  water,  and  easily  attracting  moisture  from  the  air. 
It  becomes  blue  when  gently  heated  to  expel  water  of  crys- 
tallization, and  if  heated  more  strongly,  evolves  brown 
nitrous  fumes,  leaving  black  oxide  of  cobalt. 

48.  The  indication  of  nickel  may  be  confirmed  by  adding 
to  the  original  solution  an  excess  of  ammonia  (which  gives  a 
blue  color,  especially  on  heating),  and  of  a  yellow  sulphide 
of  ammonium,  when  the  sulphide  of  nickel  first  precipitated 
will,  in  great  measure,  be  redissolved  to  a  muddy  brown 
solution. 

49.  Neither  metallic  nickel,  Ni  (which  resembles  iron), 


58  NICKEL. 

Commercial  Oxide  of  Nickel,  NiO,  is  a  dull  green  or  brown 
powder,  which  dissolves  in  hydrochloric  acid,  yielding  a  green 
solution. 

Sulphate  of  Nickel,  NiSO4.7H2O,  forms  bright-green  crys- 
tals, which  are  easily  dissolved  by  water  to  a  green  solution. 

50.  The  indication  of  aluminium  may  be  confirmed  by 
observing  the  character  of  the  precipitate  caused  by  ammonia 
in  the  original  solution..    The  hydrate  of  alumina  which  is 
then  precipitated  is  nearly  transparent,  so  that  it  might  easily 
be  overlooked,  but  that  bubbles  of  air  are  usually  entangled 
in  it.     If  the  liquid  be  warmed,  the  alumina  separates  in 
more  distinct  flakes. 

The  potash  employed  in  testing  often  contains  alumina, 
which  renders  it  the  more  necessary  to  confirm  the  result  by 
testing  the  original  solution. 

In  examining  substances  insoluble  in  water  and  acids, 
silica  is  likely  to  be  met  with  here,  as  well  as  alumina.  To 
separate  them,  the  original  acid  solution  should  be  evaporated 
to  dryness  (84),  and  the  residue  warmed  with  hydrochloric 
acid.  On  pouring  the  solution  into  a  test-tube,  the  silica 
will  be  seen  in  flakes,  and  if  these  be  filtered  off,  and  the 
solution  mixed  with  excess  of  ammonia,  the  flocculent  pre- 
cipitate of  alumina  will  be  obtained. 

51.  Metallic  Aluminium,  Al,  resembles  tin  in  appearance, 
but  is  much  lighter.    It  is  distinguished  from  all  other  white 
metals  except  platinum,  by  its  resistance  to  the  action  of 
nitric  acid,  and  from  platinum   by  its  easily  dissolving  in 
hydrochloric  acid. 


ALUM.  -  59 


COMMON  COMPOUNDS  OF  ALUMINIUM. 

Names.  Composition. 

Clay  or  silicate  of  alumina  Alumina,  silicic  acid,  water. 

Sulphate  of  alumina,  or          >      Alumi        sulphuric  acid,  water. 
Concentrated  alum  ^ 

.         ^  (      Alumina,  sulphuric  acid, 

I      Potash  (or  ammonia),  water. 

Emery  Aluminium,  oxygen. 

Acetate  of  alumina  Alumina,  acetic  acid,  water. 

Aluminate  of  soda  Alumina,  soda. 

Kryolite  Aluminium,  sodium,  fluorine. 

Clay,  being  nearly  insoluble  in  hydrochloric  and  nitric 
acids,  will  be  considered  hereafter,  as  will  Emery  and  Kryo- 
lite for  the  same  reason. 

Sulphate  of  Alumina,  Al23SO4.18Aq.,  is  sold  as  a  white 
or  grayish  opaque  mass,  of  crystalline  structure,  and  sweetish 
astringent  taste.  It  dissolves  easily  in  water,  yielding  a 
solution  which  reddens  blue  litmas.  The  sulphuric  acid 
may  be  detected  with  chloride  of  barium  (Table  H). 

Alum  may  be  either  sulphate  of  alumina  and  potash, 
KA12SO4.12Aq.,  or  sulphate  of  alumina  and  ammonia, 
NH4A12SO4.12Aq.,  or  a  mixture  of  both  salts,  according  to 
the  conditions  of  its  manufacture.  It  forms  bright  colorless 
crystals,  which  have  a  sweet  astringent  taste,  and  dissolve 
easily  in  cold  water,  yielding  a  solution  which  reddens  blue 
litmus.  When  heated  on  a  knife  or  a  piece  of  glass  alum 
easily  melts,  evolves  much  steam,  and  leaves  a  white  opaque 
swollen  mass  which  is  quite  infusible.  If  this  mass  be  held 
so  as  to  touch  the  outside  coating  of  the  flame,  the  violet- 

*  Potash-alum  is  composed  of  sulphate  of  alumina  and  sulphate 
of  potash,  whilst  ammonia-alum  contains  sulphate  of  alumina  and 
sulphate  of  ammonia. 


GO  ZINC    AND    ITS    COMPOUNDS. 

blue  tint  imparted  to  the  latter  will  indicate  the  presence  of 
potash.  Ammonia  may  be  detected  by  its  odor,  on  boiling 
the  alum  with  potash. 

Acetate  of  Alumina  or  Red  Mordant  is  sold  in  a  state  of 
solution  in  water.  It  has  an  odor  of  acetic  acid  (vinegar), 
reddens  blue  litmus,  and  if  diluted  with  much  water  and 
boiled,  yields  a  translucent  gelatinous  precipitate  of  basic 
acetate  of  alumina.  The  presence  of  acetic  acid  may  be 
proved  by  the  production  of  a,  red  color  on  adding  perchloride 
of  iron. 

Aluminate  of  Soda,  3Na2O.Al2O3,  is  a  grayish-white 
opaque  substance,  strongly  alkaline  to  the  taste,  dissolving 
easily  in  water,  yielding  a  solution  which  blues  red  litmus. 
On  adding  a  single  drop  of  diluted  hydrochloric  acid,  a  floccu- 
lent  precipitate  of  alumina  appears,  but  is  redissolved  by  an 
excess  of  the  acid.  Addition  of  ammonia  to  this  solution 
produces  the  gelatinous  precipitate  of  alumina. 

52.  To  confirm  the  presence  of  zinc,  mix  the  original 
solution  with  ammonia  in  excess,  filter,  if  necessary,  and  add 
ferrocyanide  of  potassium,  which  produces  a  white  precipitate 
of  ferrocyanide  of  potassium  and  zinc,  generally  appearing 
yellow  through  the  excess  of  ferrocyanide  of  potassium. 

Potash  produces,  in  solutions  of  zinc,  a  white  precipitate 
which  dissolves  easily  in  excess  of  potash. 
(Blowpipe  test  for  Zinc,  see  267.) 

53.  Metallic  Zinc,  Zn,  is  easily  dissolved  by  hydrochloric 
acid  or  nitric  acid,  the  latter  serving  to  distinguish  it  from 
aluminium  (51). 


ZINC    COMPOUNDS.  61 


COMMON  COMPOUNDS  OF  ZINC. 

Composition. 

Sulphate  of  zinc,  or          )        (  Oxide  of  zinc,  sulphuric  acid, 
White  vitriol  $        ( Water. 

r  I          Zinc,  oxygen. 

Carbonate  of  zinc,  or        )          Q  M      f   .       carbonic  acid. 

Calamine  ) 

Sulphide  of  zinc,  or          >          Zi        sul  hur> 
Blende  $ 

Chloride  of  zinc  Zinc,  chlorine. 


Sulphate  of  Zinc,  ZnS04.7Aq.,  is  usually  met  with  in 
shining  needle-like  crystals  which  dissolve  easily  in  water. 
The  solution  reddens  blue  litmus  paper,  and  has  a  nauseous 
metallic  taste.  The  sulphuric  acid  may  be  detected  by 
chloride  of  barium  (Table  H). 

Zinc  White,  ZnO,  is  insoluble  in  water,  but  dissolves  in 
hydrochloric  acid,  usually  effervescing  slightly  from  the 
escape  of  carbonic  acid,  which  the  oxide  of  zinc  absorbs  from 
the  air.  When  heated,  oxide  of  zinc  becomes  yellow,  but 
resumes  its  white  color  on  cooling. 

Carbonate  of  Zinc,  ZnCO3,  occurs  in  nature  as  Calamine, 
which  has  a  light  brown  color  due  to  the  presence  of  iron. 
It  is  insoluble  in  water,  but  dissolves  with  effervescence  in 
hydrochloric  or  nitric  acid.  When  the  nitric  solution  is 
mixed  with  an  excess  of  ammonia,  any  iron  which  is  present 
will  be  precipitated  as  brown  hydrated  peroxide,  and  if  this 
be  separated  by  nitration,  the  solution  will  yield  a  white  pre- 
cipitate with  sulphide  of  ammonium. 

Sulphide  of  Zinc  or  Blende,  ZnS,  also  called  Black  Jack, 
is  another  ore  of  zinc,  commonly  met  with  in  black  shining 
dodecahedral  crystals,  the  color  of  which  appears  to  be  due 
to  their  containing  sulphide  of  iron.  It  is  not  affected  by 
water,  and  dissolves  very  slowly  in  boiling  hydrochloric  acid, 


62  ZINC    COMPOUNDS. 

evolving  the  odor  of  hydrosulphuric  acid.  Nitric  acid  dis- 
solves it,  generally  causing  the  separation  of  flakes  of  sulphur; 
the  solution  behaves  as  described  above  in  the  case  of 
calamine. 

Chloride  of  Zinc,  ZnCl2,  is  commonly  sold  in  solution 
[Burnett's  disinfecting  fluid}.  The  chlorine  may  be  detected 
by  nitrate  of  silver  (Table  H).  Solid  chloride  of  zinc  is  white 
and  opaque ;  it  absorbs  moisture  rapidly  from  the  air,  becom- 
ing wet  (deliquesces). 

54.  To   confirm    the    presence  of  manganese,   boil   the 
original  solution  with  a  very  little  nitric  acid*  to  convert  any 
ferrous  salt  into  ferric  salt,  and  add  chloride  of  ammonium 
and  a  slight  excess  of  ammonia  (5).    Filter  from  any  precipi- 
tate caused  by  iron  present  as  an  impurity ;  test  one  part  of 
the  filtered  liquid  with  potassium  ferrocyanide,  which  should 
give  a  white  precipitate;    to  the  other  part  add  potassium 
dichromate,  and   heat ;    a  dark  brown  precipitate  indicates 
manganese.     (Blowpipe  test  for  Manganese,  see  268.) 

54a.  If  the  manganese  be  contained  in  the  original  sub- 
stance in  the  form  of  manganate  or  permanganate  of  potash 
it  will  not  be  detected  by  the  Table,  but  will  be  recognized 
by  the  dark  green  or  purple-red  color  of  the  solution.  (See 
below). 

55.  Metallic  Manganese,   Mn,    is  very  uncommon.      It 
resembles  iron  in  appearance,  but  when  heated  with  water  it 
causes  effervescence,  from  escape  of  hydrogen,  accompanied 
by  a  very  peculiar  odor  caused  by  compounds  of  hydrogen 
with  the  carbon  contained  in  the  metal. 

*  The  addition  of  nitric  acid  may  be  omitted  if  the  original  sub- 
stance was  dissolved  in  hydrochloric  acid  and  evolved  the  smell  of 
chlorine. 


MANGANESE  COMPOUNDS.  63 

COMMON  COMPOUNDS  OF  MANGANESE. 

Names.  Composition. 

or  } 

Sulphate  of  manganese  \ 

Permanganate  of  potash  { 

(  Manganic  acid   • 
Manganate  of  potash  <  p  ,  °,  £  oxygen 

Binoxide  of  Manganese,  MnO2,  (or  Manganese  as  it  is  often 
called)  is  found  in  nature,  as  Pyrolusite,  in  6fae&  shining 
masses  often  exhibiting  prismatic  crystals.  The  oxide  is  also 
met  with  in  dull  dark  brown  fragments  which  give  a  dark 
brown  powder.  It  is  not  attacked  by  water,  but  hydrochloric 
acid  dissolves  it  slowly,  evolving  a  strong  smell  of  chlorine. 
If  the  solution  be  filtered  (4)  and  mixed  with  ammonia  in 
excess,  it  often  gives  a  brown  precipitate  of  peroxide  of  iron, 
which-  is  a  common  impurity  of  the  mineral,  and  after  this 
has  been  filtered  off,  the  solution  will  give  a  buff  or  flesh- 
colored  precipitate  with  sulphide  of  ammonium. 

Sulphate  of  Manganese,  MnS04.5H2O,  is  met  with  (as  an 
artificial  product)  in  crystalline  masses  of  a  pinkish  color, 
easily  dissolved  by  hot  water,  yielding  a  solution  which  is 
very  nearly  colorless.  The  sulphuric  acid  may  be  detected 
by  chloride  of  barium  (Table  H). 

Permanganate  of  Potash,  K2Mn2O8,  is  commonly  sold  in 
the  state  of  solution  (Candy's  disinfectant),  known  by  its 
magnificent  purple  red  color,  which  is  unchanged  by  cold 
diluted  hydrochloric  acid,  but  vanishes  on  adding  an  excess  of 
hydrosulphuric  acid,  sulphur  being  separated.  If  a  solution 
of  permanganate  of  potash  be  mixed  with  potash  and  filtered 
once  or  twice  through  paper,  the  latter  becomes  brown  from 


64  PHOSPHATES. 

the  deposition  of  binoxide  of  manganese,  and  a  green  solution 
of  manganate  of  potash  passes  through. 

The  solid  permanganate  of  potash  forms  hard  prismatic 
crystals  which  appear  almost  black,  but  are  really  dark  red 
with  a  green  reflection,  and  are  at  once  known  by  the  intense 
purple  color  which  they  impart  even  to  cold  water. 

Manganate  of  Potash,  K2MnO4,  is  met  with  as  a  fine  green 
solution  which  becomes  red  (permanganate)  when  diluted 
with  much  water,  depositing  brown  hydrated  peroxide  of 
manganese.  Dilute  nitric  acid  produces  a  similar  change. 

56.  Several  other  substances  beside  phosphate  of  lime 
might  also  be  precipitated  here,  but  this  being  far  more 
common  than  any  of  the  others,  would  be  found  in  most 
cases  to  compose  the  precipitate.  Phosphate  of  Alumina 
(112),  Phosphate  of  Magnesia,  Oxalate  of  Lime,  and  Fluoride 
of  Calcium  are  some  other  common  substances  which  might 
be  met  with  here.  (Phosphate  of  Baryta  and  Phosphate  of 
Strontia  would  also  be  precipitated,  but  they  are  very  un- 
common.) 

In  order  to  be  quite  sure  that  phosphate  of  lime  is  present, 
the  original  solution  should  be  mixed  with  some  acetate  of 
ammonia  (prepared  by  adding  acetic  acid  to  ammonia  until 
it  reddens  blue  litmus  paper)  and  divided  into  two  parts. 

One  part  is  tested  with  oxalate  of  ammonia,  which  will 
produce  a  white  precipitate  of  oxalate  of  lime. 

The  other  part  is  tested  with  a  drop  of  perchloride  of  iron, 
which  will  give  a  white  precipitate  of  phosphate  of  iron. 

The  common  form  of  phosphate  of  lime,  Ca32PO4,  is  Bone 
Ash,  which  is  usually  sold  as  a  white  powder,  insoluble  in 
water  but  dissolving  easily  in  hydrochloric  acid,  with  slight 
effervescence,  due  to  the  escape  of  carbonic  acid  from  the 
carbonate  of  lime  always  present  in  bones,  and  often  leaving 
a  slight  dark  residue  of  charcoal. 

Superphosphate  of  Lime,  CaH42PO4,  is  commonly  sold 
as  a  gray  damp  powder,  which  dissolves  to  a  great  extent  in 
water  yielding  a  strongly  acid  solution. 


FLUOR    SPAR.  65 

57.  Phosphate  of  Magnesia  would  be  known  by  its  not 
yielding  any  precipitate  on  the  addition  of  oxalate  of  ammonia, 
as  above  directed  for  the  detection  of  lime ;  but  if  an  excess 
of  ammonia  be  afterwards  added,  and  the  solution  briskly 
stirred  (6)  a  crystalline  precipitate  of  ammonio-phosphate  of 
magnesia  will  be  deposited. 

Should  there  be  no  precipitate,  add  some  phosphate  of 
soda,  and  again  stir.  If  this  produces  a  precipitate,  it  will 
indicate  that  magnesia  has  been  precipitated  in  the  wrong 
place,  in  consequence  of  too  little  chloride  of  ammonium 
having  been  added  in  Table  A. 

The  only  common  form  of  phosphate  of  magnesia  is  that 
of  ammonio-phosphate  or  triple  phosphate  found  in  calculi, 
MgNH4PO4;  it  is  insoluble  in  water,  but  dissolves  easily  in 
hydrochloric  acid. 

58.  Oxalate  of  Lime,  CaC3O4,  would  be  precipitated  on 
mixing  its  original  solution  with  acetate  of  ammonia,  since 
it  is  insoluble  in  the  acetic  acid  thus  set  free. 

Oxalate  of  lime  may  be  easily  identified  by  its  not  effer- 
vescing when  moistened  with  hydrochloric  acid,  unless  it  has 
been  previously  heated  on  a  piece  of  glass  or  porcelain,  when 
it  becomes  converted  into  carbonate  of  lime,  which  should  be 
allowed  to  cool  and  tested  with  hydrochloric  acid.  It  may 
also  be  tested  for  oxalic  acid  according  to  (114). 

59.  Fluoride  of  Calcium,  CaF2,  or  Fluor  Spar  is  met 
with  in  greenish  or  purple  cubical  crystals.     Its  powder  re- 
sembles powdered  glass  in  appearance  and  feel.     It  is  not 
affected  by  water,  and  is  dissolved  only  to  a  slight  extent  by 
diluted  hydrochloric  acid,  the  filtered  solution  yielding  a 
flocculent  precipitate  with  ammonia. 

When  heated  on  a  knife,  or  thrown  upon  a  hot  surface, 
fluor  spar  generally  crackles  and  flies  off,  at  the  same  time 
emitting  a  peculiar  phosphorescent  light,  somewhat  resem- 
bling that  of  burning  sulphur.  It  may  be  tested  for  fluorine 
according  to  Table  G. 

.    If   fhrnminrn   hf>  nrr»spnf.  in   flip  form   nf   plirnmnfp  r»r 


66  CHROMIUM    COMPOUNDS. 

bichromate  of  potash,  it  will  not  be  detected  in  the  Table, 
but  may  be  recognized  by  the  yellow  or  red  color  of  the 
solution,  and  by  the  yellow  precipitates  which  it  gives  with 
acetate  of  lead  and  with  nitrate  of  baryta. 

60.  The  green  solution  produced  by  excess  of  potash  will 
deposit   a   green   precipitate  of  oxide   of  chromium   when 
boiled.     To  confirm  the  presence  of  chromium,  fuse  a  very 
little  of  the  original  substance  with  nitrate  of  potash,  in  a 
small  tube  (17),  when  a  bright  yellow  mass  of  chromate  of 
potash  will  be  produced.     This  may  be  dissolved  in  water, 
and  tested  with  acetate  of  lead  which  gives  a  yellow  pre- 
cipitate. 

61.  Metallic  chromium,  Cr,  is  not  likely  to  be  met  with 
in  ordinary  analysis. 

COMMON  COMPOUNDS  OF  CHROMIUM. 

Names.  Composition. 

Oxide  of  chromium  Chromium,  oxygen. 

Chrome  iron  ore  Chromium,  iron,  oxygen. 

Chromate  of  potash  and  )        (  Chromic  acid  (chromium  &  oxygen) 
) 


Bichromate  of  potash       )        (  Potash. 

Chromate  of  lead,  or        )        (  Chromic  acid, 
Chrome-yellow  j        (  Oxide  of  lead. 


Chrome-alum 


Oxide  of  Chromium,  Cr2O3,  is  a  green  powder  which  is 
insoluble  in  water,  but  generally  dissolves,  at  least  partly,  in 
hydrochloric  acid,  yielding  a  green  solution.  If  it  has  been 
heated  to  redness,  it  is  insoluble  in  hydrochloric  and  in 
nitric  acids,  but  may  be  dissolved  by  boiling  it  with  strong 
nitric  acid,  and  adding  a  little  chlorate  of  potash,  which  oxi- 
dizes the  chromium  into  chromic  acid,  recognizable  by  the 
yellow  precipitate  of  chromate  of  lead  which  is  obtained  on 
adding  acetate  of  ammonia  (56)  and  acetate  of  lead. 

Chrome  Iron  Ore,  FeCrO,,  is  a  hard  mineral,  of  a  dark 


CHROMIUM    COMPOUNDS.  67 

brown  or  dark  green  color,  which  is  almost  insoluble  in 
acids,  and  may  be  treated  in  a  similar  manner  to  the  pre- 
ceding, in  order  to  detect  the  chromium. 

Chromate  of  Potash,  K2CrO4,  forms  bright  yellow. crystals 
easily  soluble  in  water,  giving  a  yellow  solution,  which  be- 
comes orange  red  when  mixed  with  hydrochloric  acid,  from 
the  production  of  bichromate  of  potash.  Hydrosulphuric 
acid  added  in  large  excess  to  the  acidified  solution  converts 
it  into  green  chloride  of  chromium,  rendering  it  opaque  from 
the  separation  of  sulphur. 

Bichromate  of  Potash,  K2CrO4.CrO3,  is  sold  in  large  ir- 
regular crystals  of  a  fine  orange  red  color,  easily  soluble  in 
water.  The  solution  of  this  salt  also  becomes  green  when 
mixed  with  hydrochloric  and  excess  .of  hydrosulphuric  acids. 

Chromate  of  Lead  has  been  described  at  page  29. 

Chrome  Alum,  KCr2SO4.12Aq.,  forms  a  dark  purple 
crystals,  which  dissolve  in  water,  yielding  a  purple  solution, 
becoming  green  when  boiled. 

62.  Examples  for  Practice  in  Table  D The  following 

substances  may  be  analyzed  (10): — 


Chrome  alum 
Sulphate  of  nickel 
Iron  pyrites 
Sulphate  of  manganese 
Sulphide  of  iron 


Oxide  of  zinc 
Binoxide  of  manganese 
Common  alnm 
Sulphate  of  iron 


Peroxide  of  iron 
Sulphate  of  zinc 
Bone-ash 
Metallic  zinc. 


68 


TABLE    E. 


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of  ammonium  has  bei 
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BARIUM    COMPOUNDS.  69 


NOTES  TO  TABLE  E. 

64.  To  confirm  the  presence  of  barium,  add  hydrofluo- 
silicic  acid  to  a  portion  of  the  original  solution,  and  stir  well 
with  a  glass  rod  (6),  when  a  semi-transparent  crystalline  pre- 
cipitate of  silicon1  uoride  of  barium  will  be  deposited. 

Or,  dissolve  the  carbonate  of  ammonia  precipitate  in  acetic 
acid,  and  add  chromate  of  potash,  which  produces  a  yellow 
precipitate  of  chromate  of  baryta. 

65.  Metallic  Barium,  Ba,  is  very  uncommon.    It  speedily 
oxidizes  when  exposed  to  the  air,  becoming  converted  into 
baryta. 

COMMON  COMPOUNDS  OF  BARIUM. 

Names.  Composition. 

Sulphate  of  baryta,  or   )    -„ 

Heavy  spar  (    Baryta  (oxide  of  barium),  sulphuric  acid. 

Carbonate  of  baryta,  or  )    „ 

Witherite  }  Baiyta'  carbomc  *C1(L 
Chloride  of  barium  Barium,  chlorine,  water. 

Nitrate  of  baryta  Baryta,  nitric  acid. 

Hydrate  of  baryta  Baryta,  water. 

Baryta  Barium,  oxygen. 

Chlorate  of  baryta  Baryta,  chloric  acid. 

Chromate  of  baryta  Baryta,  chromic  acid. 

Sulphate  of  Baryta,  BaSO4,  being  insoluble  in  water  and 
acids,  will  be  considered  hereafter. 

Carbonate  of  Baryta,  BaCO3,  is  found  as  a  grayish-white, 
heavy  earthy  mineral,  insoluble  in  water,  but  dissolving,  with 
effervescence,  in  hydrochloric  acid.  If  a  glass  rod  or  a 
platinum  wire  be  dipped  into  the  solution,  and  held  in  the 
margin  of  a  flame  (70),  it  will  tinge  the  flame  green.  The 
artificial  carbonate  of  baryta  is  &  pure  white  earthy  powder, 
which  usually  gives  a  milky  solution  in  hydrochloric  acid, 
from  a  slight  impurity  of  sulphate  of  baryta,  not  easily 
filtered  off. 


70  BARIUM    COMPOUNDS. 

Chloride  of  Barium  or  muriate  of  barytes,  BaCl2.2Aq., 
forms  transparent  flat  crystals,  which  dissolve  easily  in 
water.  The  chlorine  may  be  detected  by  nitrate  of  silver 
(Table  H). 

Nitrate  of  Baryta,  Ba2NO3,  forms  colorless  crystals, 
which  are  dissolved  by  water.  When  heated  in  a  dry 
tube  (17),  it  evolves  brown  fumes  of  nitric  peroxide,  and 
leaves  an  infusible  residue  of  baryta. 

Hydrate  of  Baryta,  BaH2O2,  is  sold  either  in  colorless 
crystals  or  as  a  white  powder.  The  crystals  soon  become 
opaque  when  exposed  to  the  air,  losing  water  and  absorbing 
carbonic  acid.  Hydrate  of  baryta  dissolves  easily  in  water, 
yielding  a  strongly  alkaline  solution,  soon  rendered  milky  by 
the  carbonic  acid  of  the  air,  especially  if  shaken  in  a  test- 
tube  which  has  been  breathed  into. 

Baryta,  BaO,  is  sold  as  a  gray  porous  solid,  which  be- 
comes very  hot  when  moistened  with  water,  and  crumbles  to 
a  white  powder  of  hydrate  of  baryta. 

Chlorate  of  Baryta,  Ba2ClO3,  forms  colorless  crystals 
soluble  in  water.  Hydrochloric  acid  colors  the  solution 
yellow,  on  applying  heat,  by  decomposing  the  chloric  acid, 
and  evolves  a  chlorous  smell.  Hydrosulphuric  acid  added 
to  this  solution  yields  a  white  deposit  of  sulphur.  Strong 
sulphuric  acid  reddens  the  chlorate,  and  causes  explosion  on 
heating. 

Chromate  of  Baryta,  BaCr04,  is  a  bright  yellow  powder, 
insoluble  in  water,  but  soluble  in  hydrochloric  acid,  giving  a 
yellow  solution,  which  becomes  green  when  heated  with 
alcohol  or  allowed  to  remain  in  contact  with  metallic  zinc, 
chloride  of  chromium  being  formed. 

66.  To   confirm    the    presence  of  strontium,  apply   the 
colored  flame  test  (70)  to  the  original  substance. 

67.  Metallic  Strontium,  Sr,  is  a  rarity;  it  is  soon  con- 
verted into  strontia  by  absorbing  oxygen  from  the  air. 


STRONTIUM    COMPOUNDS.  71 


COMMON  COMPOUNDS  OF  STRONTIUM. 

Names.  Composition. 

Strontia  (oxide  of  strontium), 


Nitrate  of  strontia  ^      Nitric  acid, 

Water. 


} 


Strontia>  snIPhuric  add' 
Strontia,  carbonic  acid. 


Nitrate  of  Strontia,  Sr2"NO3.5Aq.,  forms  colorless  crystals, 
which  are  easily  dissolved  by  water  ;  paper  dipped  into  the 
solution  and  held  in  the  margin  of  a  flame  (70)  will  color  it 
with  flashes  of  crimson.* 

-  When  heated  in  a  dry  tube  (17),  nitrate  of  strontia  evolves 
water  and  brown  fumes  of  nitric  peroxide,  leaving  an  infu- 
sible residue  of  strontia.     Nitrate  of  strontia   which    has 
been  crystallized  by  boiling  down  its  solution  contains  no 
water. 

Sulphate  of  Strontia,  SrS04,  being  nearly  insoluble  in 
water  and  acids,  will  not  be  considered  here. 

Carbonate  of  Strontia,  SrCO3,  is  usually  found  as  a  green- 
ish mineral,  which  is  insoluble  in  water,  but  dissolves  in 
hydrochloric  acid  with  effervescence.  Paper  dipped  into  the 
solution  colors  flame  crimson*  (70). 

68.  Oxalate  of  Ammonia  also  forms  precipitates  in  solu- 
tions containing  barium  and  strontium,  so  that  it  can  never 
be  used  as  a  test  for  calcium,  unless  the  absence  of  those 
metals  has  been  previously  ascertained. 

69.  Metallic  Calcium,  Ca,  is  not  likely  to  be  met  with 

*  Some  care  is  requisite  to  avoid  mistaking  the  orange-red  tint 
which  calcium  imparts  to  flame,  for  the  crimson  of  strontium. 


72  LIME    COMPOUNDS. 

in  ordinary  analysis ;  it  quickly  absorbs  oxygen  from  the 
air,  and  is  converted  into  lime. 


COMMON  COMPOUNDS  OF  CALCIUM. 

Names.  Composition. 


"Mm* 


Carbonate  of  lime,  or  )  T.  ,  ., 

«,    ,,  Lime,  carbonic  acid. 

Sulpha^  of  lime,  or  j         Lime>  sulphurio 

Chloride  of  calcium  Calcium,  chlorine. 

Chloride  of  lime,  or  }       £  Lime,  hypochlorous  acid, 

Bleaching  powder,  or  <  Chloride  of  calcium, 

Hypochlorite  of  lime  y       (_  Water. 

Oxalate  of  lime  Lime,  oxalic  acid. 

Phosphate  of  lime  Lime,  phosphoric  acid. 

Superphosphate  of  lime  Lime,  phosphoric  acid,  water. 

Fluoride  of  calcium  Calcium,  fluorine. 

Quick  Lime,  CaO,  is  a  grayish  white  earthy  solid,  which 
becomes  hot  when  moistened  with  water,  and  crumbles  after 
a  time  to  a  white  powder  of  hydrate  of  lime. 

Hydrate  of  Lime,  CaH2O2,  is  a  light  white  powder,  which 
is  not  visibly  dissolved  by  water,  but  dissolves  easily  in 
hydrochloric  acid,  usually  effervescing  slightly,  from  the 
presence  of  a  little  carbonate  of  lime.  When  shaken  with 
cold  water,  and  filtered,  hydrate  of  lime  gives  a  solution 
which  turns  red  litmus  blue,  and  becomes  milky  when  shaken 
in  a  test-tube  which  has  been  breathed  into,  from  the  pre- 
cipitation of  carbonate  of  lime. 

Lime-water  may  be  recognized  by  the  test  just  given. 

Carbonate  of  Lime,  CaCO3,  occurs  in  nature  in  several 
forms,  all  of  which,  however,  are*  insoluble  in  water,  but 


CALCIUM    COMPOUNDS.  73 

dissolve  easily  in  hydrochloric  acid,  with  brisk  effervescence 
from  escape  of  carbonic  acid. 

Limestone  and  Chalk,  which  are  the  most  impure  of  the 
natural  varieties  of  carbonate  of  lime,  generally  yield  a 
slight  flocculent  precipitate  of  alumina  when  their  hydro- 
chloric solution  is  tested  with  ammonia,  and  a  green  tinge, 
from  the  presence  of  iron,  when  sulphide  of  ammonium  is 
added  to  the  ammoniacal  liquid.  Marble  Iceland  Spar,  and 
prepared  chalk,  which  are  purer  forms  of  the  carbonate,  do 
not  behave  in  the  same  way. 

Magnesium  Limestone,  or  Dolomite,  CaMg2CO3,  which 
contains  the  carbonates  of  lime  and  magnesia,  may  be  iden- 
tified by  dissolving  it  in  diluted  hydrochloric  acid,  adding 
chloride  of  ammonium,  ammonia,  and  carbonate  of  ammonia, 
to  precipitate  the  lime,  boiling,  filtering,  and  testing  the 
solution  for  magnesia  with  phosphate  of  soda,  after  proving, 
by  the  addition  of  oxalate  of  ammonia,  that  all  the  lime  has 
been  separated. 

Sulphate  of  Lime,  CaSO4,  does  not  visibly  dissolve  in 
water,  although  if  the  solution  be  filtered,  a  small  quantity 
of  the  salt  will  be  found  in  solution.  The  sulphuric  acid 
may  be  detected  by  chloride  of  barium  (Table  H).  Hydro- 
chloric acid  dissolves  it  to  a  greater  extent,  but,  unless  after 
prolonged  boiling,  it  might  easily  be  concluded  that  sulphate 
of  lime  was  not  dissolved  by  water  or  acids,  so  that  it  is 
often  found  among  substances  of  that  class  (Table  I). 

The  several  varieties  of  sulphate  of  lime  differ  consider- 
ably in  appearance. 

Gypsum,  CaSO4.2HaO,  is  a  grayish-white,  opaque, 
earthy,  brittle  mineral. 

Fibrous  gypsum  is  made  up  of  parallel  silky  fibres,  which 
are  white,  gray,  or  pink. 

Selenite  is  transparent,  or  nearly  so,  either  colorless,  or 
brownish-gray  in  color,  and  easily  split  into  plates  with  a 
knife. 

Plaster  of  Paris  (calcined  gypsum}  is  a  fine  white  oowder 


74  COLORED    FLAME    TEST. 

which  sets  into  a  solid  mass  after  a  few  minutes,  if  mixed 
with  water  to  a  thin  paste. 

Chloride  of  Calcium  is  sold  in  three  forms.  The  crys- 
tallized chloride,  CaCl2.6Aq.,  forms  colorless  transparent 
crystals  which  rapidly  absorb  water  from  the  air,  and  are 
extremely  soluble  in  water.  Another  variety  is  the  porous 
chloride,  forming  a  white  or  grayish-white  porous  mass, 
CaCl2.2Aq.,  which  becomes  wet  (deliquesces)  very  rapidly 
when  exposed  to  air,  and  dissolves  easily  in  water.  The 
fused  chloride,  CaCl2,  has  similar  properties,  but  is  a  gray 
fibrous  crystalline  solid. 

The  chlorine  may  be  detected  by  nitrate  of  silver. 
(Table  H.) 

Chloride  of  Lime,  or  bleaching  powder,  2CaHClO2.CaCl2. 
2H2O,  is  a  white  earthy  powder,  which  has  a  strong  smell  of 
hypochloric  acid,  resembling  that  of  chlorine.  It  is  partly 
dissolved  by  water,  and  entirely  by  hydrochloric  acid,  with 
effervescence,  evolving  a  powerful  odor  of  chlorine.  Litmus 
paper  is  at  once  bleached  by  the  solution. 

Oxalate  of  Lime,  CaC3O4,  in  a  pure  state,  is  a  white 
powder,  insoluble  in  water,  but  soluble  in  hydrochloric  acid. 
The  method  of  identifying  it  has  been  described  at  (58). 

Phosphate  and  Superphospate  of  Lime  have  also  been 
described  at  (56). 

Fluoride  of  Calcium  will  be  found  described  at  (59). 

70.  Colored  Flame  Test. — Although  this  test  will  be 
more  fully  described  in  the  Exercises  with  the  Blowpipe,  it 
is  necessary  to  refer  to  it  here,  because  it  affords  so  valuable 
a  confirmation  of  the  results  obtained  by  liquid  tests  in 
Table  E. 

The  chlorides  of  the  metals  furnish  the  most  distinct 
colored  flames,  since  they  are  more  easily  vaporized  and 
mingled  with  the  gases  of  the  flame,  when  the  hydrogen 
abstracts  the  chlorine,  and  the  metallic  vapor  burns  with  its 
characteristic  tint.  Hence  the  substance  to  be  tested  should 
be  dissolved,  if  possible,  in  hydrochloric  acid. 


COLORED    FLAME    TEST. 


75 


The  best  flame  for  this  test  is  that  of  a   Bunsen's    air- 
burner  (fig.  23)  ;  but  if  this  be  not  at  hand,  a  fair  substi- 


Fia. 24. 


FIG.  23. 


Bunsen's  Burner. 


tute  may  be  made  by  placing  a  small  glass  funnel  (a,  fig.  24), 
with  a  rather  wide  neck,  over  a  gas-burner,  as  shown  in 
fig.  24,  where  (6)  is  one  of  the  flattened  burners  often  em- 
ployed for  blowpipe  experiments.  The  funnel  is  placed  over 
the  jet  before  the  gas  is  lighted ;  the  gas  is  then  turned  on 
to  a  moderate  extent,  when  it  mixes  with  the  air  passing  up 
through  the  funnel,  and  by  gradually  diminishing  the  supply 
of  gas,  it  may  be  made  to  burn  with  a  nearly  non-luminous 
flame,  in  the  margin  of  which  the  glass  rod,  or,  better, 
platinum  wire  (74),  moistened  with  the  liquid  under  exami- 
nation, should  be  held. 

Fia.2). 


76 


COLORED    FLAME    TEST. 


be  supported,  so  that  a  passage  for  air  may  be  left  between 
the  glass  and  the  jet. 

FIG.  26. 


A  spirit-lamp  (fig.  26)  may  be  used  when  gas  is  not 
attainable,  though  it  does  not  give  so  good  results  as  the 
gas-flame. 

II.  Examples  for  Practice  in  Table  E. — The  following 
compounds  may  serve  as  exercises  in  this  Table  (10) : — 


Chloride  of  barium 
Nitrate  of  strontia 
Carbonate  of  baryta 


Chloride  of  calcium 

Carbonate  of  lime  (chalk  or  marble) 

Sulphate  of  lime  (plaster  of  Paris). 


TABLE    F. 


77 


rj 

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CD 

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1  1  1  *  5  ^inl  "i 

^  • 

£ 

2       £  *  bo 

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C  S  "^   o 

issium,  Sodium, 
TABLE  F. 

ratlier  strong  solution 
;ance,  and  stir  it  (73)  i 
TARTARIC  ACID,* 
or  with 

IILORIDE  OP  PLATINUM 
a  slip  of  glass  (76). 
pitate  formed  in  lines. 
Presence  of 
Potassium  (77). 

snough  tartaric  acid  m 
previously  acidified  w 
ate  before  testing  with 
alkaline  by  potash  bef 

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M          ^           0 

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78 


PLATINUM    WIRE. 


EXPLANATIONS  AND  INSTRUCTIONS  ON 
TABLE  F. 

73.  The  precipitation  of  potassium  with  tartaric  acid  or 
bichloride  of  platinum,  and  of  sodium  with  antimoniate  of 
potash,  is  more  readily  effected  by  stirring  on  a  slip  of  glass 
than  in  a  test  tube. 

Take  a  clean,  dry  slip  of  window-glass ;  dip  a  glass  rod  (6) 
into  the  solution  to  be  tested,  and  place  the  drop  so  withdrawn 
upon  the  slip  of  glass.  Wipe  the  rod  clean,  and  dip  it  into  the 
test,  placing  the  drop  withdrawn  by  the  side  of  the  other ; 

notice  that  both  drops 
are    clear,    and    stir 
them  briskly  together 
with   the  end  of  the 
glass       rod,      which 
should  be   moved  in 
circles,  but  not  hard 
enough  to  scratch  the 
glass  (fig.  27).     The  preci- 
pitate will  then  be  deposited 
in  lines  (fig.  28)  upon  those 
parts   of   the    slip   of   glass 
which  have  been  rubbed  by 
the  rod. 

74.  The  platinum  wire  for  this  purpose  should  be  very 
thin,  so  that  one  inch   may  weigh  ^  grain.     A  piece  about 
three  inches  long  should  be  fixed  into  a  glass  handle,  which 
is  conveniently  made  by  softening  the  centre  of  a  narrow 
glass  tube  in  the  blowpipe-flame  (fig.  15),  drawing  it  out  to 

FIG.  29. 


FIG.  27. 


FIG.  28. 


a  narrow  neck  (fig.  19),  and  cutting  it  off  at  a  ;  the  platinum 
wire  is  then  inserted  (fig.  29),  and  the  glass  fused  round  it 


AMMONIA    AND    ITS    COMPOUNDS.  79 

Since  all  platinum  wire  which  has  been  fingered  tinges 
flame  yellow  (sodium  having  been  derived  from  the  perspi- 
ration of  the  skin),  it  must  be  cleansed  before  use  by  holding 
it  in  the  margin  of  the  flame  until  a  yellow  tinge  is  no  longer 
visible. 

NOTES  TO  TABLE  F. 

15.  Ammonium,  NH4,  is  not  known  to  have  any  separate 
existence,  but  it  is  often  very  convenient  to  represent  the 
nitrogen  and  hydrogen  in  the  salts  of  ammonia,  as  existing 
in  the  form  of  a  compound  metal,  capable  of  taking  the  same 
part  in  the  composition  of  those  salts  as  is  taken  by  potas- 
sium and  sodium  in  their  salts. 

COMMON  COMPOUNDS  OF  AMMONIA. 

Names.  Composition. 

\       r  A  •        ( Nitrogen, 

Solution  of  ammonia,  or      \     j  Ammonia,    <  ^  droo-  n 
Liquor  ammonite  )       ( Water.  \     J       o 

Carbonate  of  ammonia  Ammonia,  water,  carbonic  acid. 

Sulphate  of  ammonia  Ammonia,  water,  sulphuric  acid. 

Nitrate  of  ammonia  Ammonia,  water,  nitric  acid. 

Sulphide  of  ammonium  Ammonia,  hydrosulphuric  acid. 

Chloride  of  ammonium,  or  j        Ammonia   hydrochloric  acid. 

feal-ammoiiiac  ) 

Oxalate  of  ammonia  Ammonia,  water,  oxalic  acid. 

Solution  of  Ammonia,  NH3,  has  the  strong  odor  of  harts- 
horn, does  not  effervesce  with  dilute  hydrochloric  acid,  and 
leaves  no  residue  when  evaporated  on  a  slip  of  glass. 

Chloride  of  Ammonium,  or  muriate  of  ammonia,  or  hydro- 
chlorate  of  ammonia,  or  sal-ammoniac,  NH4C1,  is  sold  either 
in  white  crystals  or  in  translucent  fibrous  masses,  usually 
stained  brown  in  places.  It  is  very  easily  dissolved  by  water. 
It  has  no  ammoniacal  smell,  and  when  heated  on  a  knife  or 
a  slip  of  glass,  it  evaporates  in  white  fumes  without  melting. 
The  chlorine  may  be  detected  with  nitrate  of  silver.  (Table 

TT  \ 


80  AMMONIACAL    SALTS. 

Carbonate  of  ammonia,  or  sesquicarbonate  of  ammonia, 
or  Preston  salts,  2(NH4)2CO3.CO2,  lias  a  powerful  odor  of 
.ammonia.  It  is  usually  sold  in  white  opaque  lumps,  which 
are  transparent  when  freshly  prepared.  Carbonate  of  am- 
monia dissolves  easily  in  water,  yielding  a  solution  which 
blues  red  litmus  paper,  and  effervesces  violently  with 
hydrochloric  acid,  in  consequence  of  the  escape  of  carbonic 
acid. 

Sulphate  of  ammonia,  (NH4)2SO4,  forms  prismatic  crys- 
tals, which  are  colorless  when  pure,  but  in  their  impure  state 
have  a  brownish  color.  It  dissolves  easily  in  water,  and 
has  no  ammoniacal  odor.  The  sulphuric  acid  may  be  de- 
tected by  chloride  of  barium.  (Table  H.) 

Nitrate  of  Ammonia,  NH4NO3,  is  sold  either  in  colorless 
crystals  or  in  opaque  fused  masses.  It  does  not  smell  of 
ammonia,  and  becomes  damp  on  exposure  to  air ;  easily 
soluble  in  water.  When  heated  on  a  slip  of  glass,  it  melts 
very  easily,  boils,  and  passes  off  entirely  as  nitrous  oxide  gas 
and  steam.  The  nitric  acid  may  be  detected  as  in  Table  H. 

Sulphide  of  Ammonium,  or  hydrosulphate  of  ammonia, 
(NH4)2S,  is  common  in  a  state  of  solution  only. 

The  solution  is  yellow  (though  colorless  when  quite  freshly 
prepared),  and  has  a  very  offensive  ammoniacal  smell,  and 
an  alkaline  reaction.  The  addition  of  hydrochloric  acid 
causes  a  milkiness,  due  to  the  precipitation  of  sulphur,  and 
an  escape  of  hydrosulphuric  acid,  recognized  by  its  odor. 

Oxalate  of  Ammonia,  (NH4)2C2O4.Aq.,  forms  shining, 
white,  needle-like  crystals,  which  are  free  from  ammoniacal 
smell,  and  dissolve  easily  in  water.  The  oxalic  acid  may  be 
detected  according  to  Table  H. 

76.  The  precipitate  produced  by  tartaric  acid  is  the  bi- 
tartrate  of  potash,  KIIC4H4O6.  The  (yellow)  precipitate 
produced  by  platinum  chloride  is  the  platinochloride  of  potas- 
sium, 2KCl.PtCl4.  Since  ammonium  is  precipitated  by  the 
same  tests,  it  is  absolutely  necessary  to  prove  its  absence 


POTASH    SALTS.  81 

Should  platinum  chloride  produce  a  dark  red  color,  iodine 
is  probably  present.  (See  Iodide  of  Potassium  (77).) 

77.  Metallic  Potassium,  K,  is  not  met  with  in  ordinary 
analysis.  It  is  oxidized  immediately  by  exposure  to  air, 
and  takes  fire  in  contact  with  water,  burning  with  a  violet 
flame. 

COMMON  COMPOUNDS  OF  POTA.SSIUM. 
Names.  Composition. 

Nitrate  of  potash,  or  )        (  Potash  j  P°tassium> 


Nitric  ad?"' 

Potash>  carbonio 

Bicarbonate  of  potash  Potash,  carbonic  acid,  water. 

Sulphate  of  potash  Potash,  sulphuric  acid. 

Bisulphate  of  potash  Potash,  sulphuric  acid,  water. 

Chloride  of  potassium  Potassium,  chlorine. 

Hydrate  of  potash  Potash,  water. 

Bitartrate  of  potash  Potash,  tartaric  acid,  water. 


Chlorate  of  potash  Potash,  chloric  acid. 

Fen-ocyanideof  potassium,  or 


Prussiate  of  potash  iron,  water. 


)       j 
*        ( 


Potassi,lm,  cyanogen,  iron. 


Cyanide  of  pot^um  *°£1™-  ^^  { 

Iodide  of  potassium  Potassium,  iodine. 

Acid  oxalate  of  potash  Potash,  oxalic  acid,  water. 

Silicate  of  potash  Potash,  silicic  acid. 

Soft  soap  Potash,  oleic  acid,  water. 

Nitre,  or  nitrate  of  potash,  KNO3,  is  easily  soluble  in 
water,  and  readily  deposits  in  prismatic  crystals  from  a  hot 
and  strong  solution  allowed  to  cool. 

Placed  on  the  point  of  a  knife  and  held  in  the  margin  of  a 
flame  (70),  it  melts,  boils,  and  colors  the  flame  blue  violet. 


82  SALTPETRE.       CHLORATE    OF    POTASH. 

Heated  in  a  dry  tube  (17),  it  easily  melts  to  a  clear  liquid, 
in. which  a  piece  of  wood  or  paper  burns  with  vivid  defla- 
gration. Brown  nitrous  fumes  may  afterwards  be  seen  and 
smelt  in  the  upper  part  of  the  tube. 

The  nitric  acid  may  be  detected  according  to  Table  H. 

Nitre  is  met  with  in  commerce  in  several  forms. 

The  grough,  or  impure  nitre,  as  imported  from  India,  con- 
sists of  small  brownish  irregular  crystals,  owing  its  color  to 
the  presence  of  vegetable  matter  from  the  earth  out  of  which 
it  is  extracted. 

The  common  saltpetre  of  the  shops  forms  colorless  irregu- 
lar crystalline  lumps. 

Refined  saltpetre  forms  colorless  prismatic  crystals,  often 
marked  with  longitudinal  grooves,  or  else  a  pure  white  crys- 
talline powder  (saltpetre  flour). 

Sal  Prynelle  is  saltpetre  which  has  been  melted  and  cast 
into  the  form  of  opaque  white  bullets. 

Chlorate  of  Potash,  KC1O3,  forms  colorless  flat  crystals. 
It  is  not  easily  soluble  in  cold  water.  Hot  water  dissolves 
it,  but  readily  deposits  it  in  flat  crystals  on  cooling.  The 
solution  of  chlorate  of  .potash  becomes  yellowish  and  emits  a 
chlorous  odor  when  heated  with  hydrochloric  acid,  the 
chloric  acid  being  decomposed,  and  when  hydrosulphuric 
acid  is  added  to  the  acidified  solution,  a  white  milky  precipi- 
tate of  sulphur  is  obtained. 

Heated  in  a  dry  tube  (17),  it  easily  melts  to  a  clear  liquid, 
which  soon  boils  and  evolves  oxygen,  recognized  by  its 
kindling  into  a  blaze  a  spark  at  the  end  of  a  match  held  at 
the  mouth  of  the  tube. 

Carbonate  of  Potash,  K2C03,  soon  becomes  damp  (deli- 
quesces) when  exposed  to  air,  from  absorption  of  water.  It 
dissolves  easily  in  cold  water,  yielding  a  very  alkaline  solu- 
tion which  effervesces  briskly  on  adding  hydrochloric  acid. 

The  carbonate  of  potash  which  is  known  as  American  pot- 
ash, or  pearlash,  forms  bluish-white  half-fused  lumps.  Salt 
of  tartar  is  a  white  crvstalline  nowder. 


POTASSIUM    COMPOUNDS.  83 

Bicarbonate  of  Potash,  KHCO,,  is  sold  either  in  transparent 
prismatic  crystals,  or  as  a  white  powder.  It  does  not  deli- 
quesce in  air,  dissolves  less  easily  in  cold  water  than  the  car- 
bonate, and  the  solution  is  not  so  strongly  alkaline. 

When  the  solution  of  bicarbonate  of  potash  is  heated  to 
boiling  it  effervesces  slowly,  from  the  escape  of  carbonic 
acid.  If  solution  of  sulphate  of  magnesia  be  added  to  a 
solution  of  bicarbonate  of  potash  (prepared  with  cold  water) 
it  does  not  produce  a  precipitate  until  the  solution  is  boiled, 
whilst  the  carbonate  of  potash  produces  a  precipitate  without 
boiling. 

Sulphate  of  Potash,  K28O4,  forms  hard,  colorless,  prisma- 
tic crystals,  which  do  not  dissolve  very  quickly  in  cold  water. 
Its  solution  does  not  redden  blue  litmus  paper. 

Bisulphate  of  Potash,  KHSO4,  dissolves  more  easily  in 
\vater,  yielding  a  strongly  acid  solution,  reddening  blue 
litmus  paper. 

Chloride  of  Potassium,  KC1,  forms  white  cubical  crystals, 
which  crackle  (decrepitate)  when  heated  on  a  slip  of  glass, 
and  dissolve  very  easily  in  cold  water.  „  The  chlorine  may  be 
detected  by  nitrate  of  silver  (Table  H). 

Hydrate  of  Potash,  KHO  (caustic  potash,  or  potassafusa), 
is  sold  either  in  lumps  or  round  sticks  somewhat  resembling 
porcelain,  and  generally  cream-colored  (older  samples  have 
a  blue  color).  It  becomes  wet  almost  immediately  when  ex- 
posed to  air,  and  dissolves  very  quickly  in  cold  water,  pro- 
ducing much  heat,  and  a  strongly  alkaline  solution. 

The  liquor  potassce,  or  solution  of  potash,  generally  con- 
tains a  little  carbonate  of  potash,  but  it  may  be  distinguished 
from  a  solution  of  that  salt  by  its  not  effervescing  with  the 
first  drop  or  two  of  hydrochloric  acid,  the  carbonic  acid  not 
escaping  until  the  whole  of  the  hydrate  of  potash  has  been 
neutralized.  Mercuric  chloride  gives  a  bright  yellow  pre- 
cipitate with  the  solution  of  potash.  Nitrate  of  silver  gives 
a  dark  brown  precipitate. 

Bitartrate  of  Potash,  or  Cream  of  Tartar,  KHC4H4O6,  is 


84  FRUSSIATES    OF    POTASH. 

soluble  with  some  difficulty  in  cold  water,  but  dissolves  in 
boiling  water,  and  is  deposited  in  shining  crystals  on  cooling. 
The  solution  reddens  blue  litmus  paper.  Hydrochloric  acid 
easily  dissolves  it.  When  heated  on  a  slip  of  glass,  or  the 
blade  of  a  knife,  bitartrate  of  potash  blackens,  from  the 
separation  of  charcoal,  and  emits  a  peculiar  odor  of  burnt 
sugar,  due  to  the  decomposition  of  the  tartaric  acid.  The 
residue,  when  moistened  with  water,  turns  red  litmus  blue, 
and  effervesces  strongly  with  hydrochloric  acid,  the  bitar- 
trate of  potash  having  been  converted  into  carbonate. 

Cream  of  tartar  is  a  white  crystalline  powder. 

The  impure  Bitartrate  of  Potash  known  as  Argol,  is  sold 
in  irregular  crystalline  lumps  of  a  brown  or  dark  purple 
color,  derived  from  the  grape-juice  which  deposits  it.  Such 
Argol  often  contains  much  tartrate  of  lime.  Refined  Argol 
forms  white  crystalline  lumps. 

Chr  ornate  and  Bichromate  of  Potash  were  described  at  (61). 

Ferrocyanide  of  Potassium,  K4C6N6Fe.3Aq.,  is  sold  in 
yellow  crystalline  masses.  It  dissolves  easily  in  water  to  a 
yellow  solution,  which  becomes  blue  when  mixed  with  hydro- 
chloric acid  and  warmed,  at  the  same  time  evolving  the 
peculiar  odor  of  prussic  acid.  Perchloride  of  iron  gives  a 
dark-blue  precipitate  of  Prussian  blue  with  the  solution  of 
ferrocyanide  of  potassium. 

Ferridcyanide,  or  Ferricyanide  of  Potassium,  K3C6N6Fe, 
forms  dark-red  prismatic  crystals,  which  dissolve  easily  in 
water,  giving  a  green  solution.  The  solution  gives  an 
intensely  blue  precipitate  with  sulphate  of  iron. 

Cyanide  of  Potassium,  KCN,  is  sold  in  white  porcelain-like 
masses  or  sticks,  which  smell  of  prussic  acid,  and  slightly  of 
ammonia,  resulting  from  decomposition.  The  cyanide  soon 
becomes  damp  in  air,  and  dissolves  very  easily  in  cold  water. 
The  solution  is  strongly  alkaline.  Commercial  cyanide  of 
potassium  always  contains  carbonate  and  cyanate  of  potash, 
so  that  it  effervesces  strongly  on  addition  of  hydrochloric  acid, 
evolving  a  powerful  odor  of  prussic  acid. 


POTASH    SALTS.  85 

The  cyanogen  may  be  detected  according  to  (98). 

Iodide  of  Potassium,  or  hydriodate  of  potash,  KI,  forms 
white  cubical  crystals,  often  brownish  after  exposure  to  the 
air  of  the  laboratory,  from  separation  of  a  little  iodine.  It 
dissolves  very  easily  in  cold  water.  If  the  solution  be  boiled 
with  a  little  nitric  acid,  it  evolves  violet  vapors  of  iodine. 

Acid  Oxalate  of  Potash,  or  salt  of  sorrel,  or  essential  salt 
of  lemons,  may  be  either  the  binoxalate,  KHC2O4.Aq.,  or 
quadroxalate  of  potash,  KH32C2O4.2Aq.  It  forms  hard 
white  crystals,  not  easily  dissolved  by  cold  water,  but  soluble 
in  hot  water,  yielding  a  solution  which  strongly  reddens  blue 
litmus.  When  heated  on  a  knife-blade  or  a  slip  of  glass,  the 
oxalate  (is  not  blackened,  like  the  bitartrate,  but)  is  con- 
verted into  carbonate  of  potash,  which  may  be  recognized  by 
its  strongly  bluing  moistened  red  litmus,  and  effervescing 
when  moistened  with  hydrochloric  acid. 

Silicate  of  Potash,  K4SiO4,  or  Soluble  Glass,  is  sold  either 
as  a  gummy  liquid  or  in  fused  masses,  which  dissolve  slowly 
in  water.  The  solution  of  silicate  of  potash  is  strongly  alka- 
line; when  diluted  hydrochloric  acid'is  gradually  added  to  it, 
slight  effervescence  generally  takes  place,  from  the  presence 
of  a  little  carbonate  of  potash,  and  when  the  solution  is 
nearly  neutralized,  the  silicic  acid  begins  to  separate  in  the 
gelatinous  form,  especially  on  heating,  sometimes  converting 
the  whole  solution  into  a  jelly.  The  presence  of  silicic  acid 
may  be  established  beyond  doubt  according  to  (118). 

Soft  Soap,  or  Oleate  of  Potash,  KC18H33O2,  is  known  by 
its  peculiar  appearance  and  smell.  It  dissolves  in  water, 
yielding  an  alkaline  solution,  which  becomes  milky  with 
diluted  hydrochloric  acid,  from  the  separation  of  oleic  acid. 
On  boiling  the  acidified  solution,  the  oleic  acid  collects  on 
the  surface  as  an  oily  layer. 

1Q.  Since  a  very  minute  quantity  of  sodium  will  impart 
a  distinct  yellow  color  to  flame,  it  often  happens  that  a  little 
of  this  substance  present  as  an  impurity  is  regarded  by  the 

ITIOV      otMon     orl  If  *}     -i          f*     1  4-"  4-  4-        •£*    4-V»  V* 


86  DETECTION    OP    SODIUM. 

stance  under  examination.  To  avoid  error,  some  collateral 
evidence  must  be  sought  for.  Thus,  it  should  be  ascer- 
tained whether  the  substance  under  examination  possesses 
the  characters  of  any  of  the  compounds  of  sodium  described 
(in  80). 

If  the  original  solution  be  neutral  or  alkaline  to  test-paper, 
and  no  metal  has  been  found  by  the  application  of  any  pre- 
vious tests,  then  it  may  be 'inferred,  if  the  substance  imparts 
a  distinct  bright  yellow  color  to  the  flame,  that  sodium  is  an 
essential  constituent  of  it. 

'TB.  Although  antimoniate  of  potash  is  a  very  excellent 
test  for  sodium,  when  the  solution  is  freshly  prepared,  it  does 
not  answer  so  well  in  dilute  solutions  containing  sodium,  if 
the  antimoniate  has  been  kept  for  some  time  in  solution. 
Another  objection  to  the  test  is  the  circumstance  that  very 
small  quantities  of  lime,  and  some  other  bases,  will  give  bulky 
precipitates  with  the  antimoniate  of  potash,  altogether  mis- 
leading the  analyst.  Free  acids  also  cause  a  milky  precipi- 
tate of  antimonic  acid. 

80.  Metallic  Sodium,  Na,  is  a  soft  metal,  with  a  silvery 
lustre  when  freshly  cut,  but  tarnishing  with  extreme  rapidity 
when  exposed  to  air.  Thrown  upo.n  water,  it  fuses,  and  the 
silvery  globule  floats  over  the  surface,  emitting  a  hissing 
sound,  from  the  escape  of  hydrogen ;  on  applying  a  light,  the 
hydrogen  burns  with  a  bright  yellow  flame. 

For  the  common  compounds  of  sodium,  see  next  page. 


CARBONATE    OF    SODA. 


87 


COMMON  COMPOUNDS  OF  SODIUM. 


Names. 

Carbonate  of  soda 

Bicarbonate  of  soda 
Hydrate  of  soda,  or 
Caustic  soda 

Soda-ash 

Common  salt 
Sulphate  of  soda 
Nitrate  of  soda 
Sulphite  of  soda 
Hyposulphite  of  soda 

Chloride  of  soda 

Phosphate  of  soda 
Arseniate  of  soda 
Biborate  of  soda,  or    ' 
Borax 

Silicate  of  soda 
Tungstate  of  soda 
Soda-soap,  or  } 

Hard  soap 


Composition. 

(  Soda  (oxide  of  sodium). 
(  Carbonic  acid. 
Soda,  carbonic  acid,  water. 

Soda,  water. 

f  Hydrate  of  soda. 
(  Carbonate  of  soda. 

Sodium,  chlorine. 

Soda,  sulphuric  acid. 

Soda,  nitric  acid. 

Soda,  sulphurous  acid,  water. 

Soda,  hyposulphurous  acid,  water. 
/  Hypochlorite  of  soda. 
(  Chloride  of  sodium,  water. 

Soda,  phosphoric  acid,  water. 

Soda,  arsenic  acid,  water. 

Soda,  boracic  acid,  water. 

Soda,  silicic  acid. 

Soda,  tungstic  acid. 
(  Soda,  stearic,  oleic,  or  palmitic 
(      acid,  water. 


Carbonate  of  soda,  Na2CO3,  dissolves  easily  in  water, 
yielding  a  strongly  alkaline  solution,  which  effervesces 
strongly,  from  escape  of  carbonic  acid,  when  hydrochloric 
acid  is  added. 

Common  washing-soda,  Na2CO.j.lOAq.,  is  crystallized 
carbonate  of  soda,  containing  nearly  two-thirds  of  its  weight 
of  water.  The  crystals  effloresce,  or  become  opaque  at  the 
surface  when  exposed  to  the  air,  from  loss  of  water.  When 
heated  on  a  knife  or  a  slip  of  glass,  crystallized  carbonate  of 
soda  melts,  boils,  evolves  much  steam,  and  leaves  a  white 
dry  residue,  which  requires  a  blowpipe-heat  to  fuse  it. 

The  carbonate  of  soda  in  powder,  which  is  sold  by  the 
druggist  is  a  bicarbonate  of  soda,  NaHC03,  which  is  less 
easily  dissolved  by  water  than  the  true  carbonate  ;  the  solu- 
tion is  not  so  strongly  alkaline,  and  effervesces  when  boiled, 


88          SODA  ASH.   PERUVIAN  SALTPETRE. 

from  escape  of  carbonic  acid.  It  may  also  be  distinguished 
from  the  true  carbonate  by  testing  it  with  sulphate  of  mag- 
nesia. See  Bicarbonate  of  Potash. 

Hydrate  of  Soda,  NaHO,  or  Caustic  Soda  is  commonly 
sold  in  opaque  white  fused  masses  which  rapidly  absorb  mois- 
ture from  the  air.  It  dissolves  very  easily  in  water,  evolving 
heat,  and  yielding  a  very  strongly  alkaline  solution  which 
effervesces  very  slightly,  if  at  all,  with  hydrochloric  acid. 

Soda-Ash  is  a  mixture  of  carbonate  of  soda  and  hydrate  of 
soda,  which  has  the  appearance  of  earthy  lumps  or  coarse 
powder.  It  dissolves  in  water,  generally  leaving  a  slight 
flaky  residue  of  impurities,  including  some  particles  of  car- 
bonaceous matter.  Its  solution  does  not  effervesce  on  the 
addition  of  the  first  two  or  three  drops  of  hydrochloric  acid, 
these  being  neutralized  by  the  hydrate  of  soda,  but  a  further 
addition  of  the  acid  decomposes  the  carbonate  of  soda,  with 
effervescence.  The  solution  generally  contains  traces  of 
alumina  and  lime. 

Common  Salt  or  Chloride  of  Sodium,  NaCl,  is  of  course 
easily  recognized  by  its  taste.  It  is  readily  soluble  in  cold 
water.  The  chlorine  may  be  detected  by  nitrate  of  silver 
(Table  H). 

Sulphate  of  Soda  or  Glauber's  Salt,  Na2SO4.10Aq.,  is 
usually  sold  in  transparent  prismatic  crystals,  which  soon  be- 
come opaque  (effloresce)  when  exposed  to  the  air,  from  loss 
of  water  of  crystallization.  It  dissolves  easily  in  water. 
The  sulphuric  acid  may  be  detected  with  chloride  of  barium 
(Table  H). 

Salt-cake  is  fused  sulphate  of  soda,  Na23O4,  and  forms 
opaque  white  masses  which  are  much  less  pure  than  the 
crystalline  sulphate,  so  that  they  do  not  give  a  clear  solution 
in  water,  and  the  solution  is  acid,  from  the  presence  of  some 
bisulphate  of  soda. 

Nitrate  of  Soda,  NaNO3,  or  Peruvian  or  Chili  saltpetre 
or  cubic  nitre,  forms  colorless  crystals  ;  the  crude  salt,  how- 


SODIUM    COMPOUNDS.  89 

ever,  is  often  brown  or  gray.  It  becomes  moist  when  ex- 
posed to  air,  and  dissolves  very  easily  in  water.  Placed  on 
the  point  of  a  knife,  and  held  in  the  margin  of  a  flame,  it 
colors  it  intensely  yellow.  When  heated  in  a  dry  tube,  it 
behaves  like  nitrate  of  potash  (77).  The  nitric  acid  may  be 
detected  according  to  Table  H. 

Sulphite  of  Soda,  Na2SO3.7Aq.,  when  freshly  prepared, 
forms  transparent  crystals,  but  they  soon  become  opaque  at 
the  surface  when  exposed  to  air.  It  dissolves  easily  in  water, 
yielding  a  solution  which  turns  red  litmus  paper  blue,  and- 
lias  a  decidedly  sulphurous  taste.  On  adding  diluted  hydro- 
chloric acid,  the  solution  evolves  the  odor  of  sulphurous  acid, 
and  hydrosulphuric  acid  renders  the  acidified  solution  milky 
by  causing  the  separation  of  sulphur. 

Hyposulphite  of  Soda,  Na2S2O3.5Aq.,  forms  brilliant 
transparent  crystals  which  dissolve  very  easily  in  water.  On 
adding  diluted  hydrochloric  acid  to  the  solution,  it  slowly 
becomes  milky  and  acquires  a  yellow  color,  from  the  sepa- 
ration of  sulphur,  the  odor  of  sulphurous  acid  being  per- 
ceptible at  the  mouth  of  the  tube.  . 

Hypochlorite  of  Soda,  NaCIO,  is  always  sold  in  solution 
under  the  names  of  Chloride  of  Soda  and  Liquor  Sodce 
Chlorinatce.  It  has  a  strong  smell  of  hypochlorous  acid 
(somewhat  resembling  that  of  chlorine).  On  adding  diluted 
hydrochloric  acid,  it  becomes  yellowish  and  evolves  a  power- 
ful odor  of  chlorine;.  Test-papers  are  at  once  bleached  by 
the  acidified  liquid. 

Phosphate  of  Soda  (common  phosphate,  orthophosphate, 
.or  rhombic  phosphate  of  soda,  Na2HPO4.12Aq.)  forms  trans- 
parent crystals,  which  effloresce,  or  become  opaque  from  loss 
of  water,  when  exposed  to  the  air.  It  dissolves  easily  in 
water,  and  the  solution  turns  red  litmus  paper  blue.  The 
phosphoric  acid  may  be  detected  according  to  Table  H. 

Arseniate  of  Soda  has  been  described  at  (35). 

Biborate  of  Soda  or  Borax,  Na2O.2B2O3.10Aq.,  is  com,- 
monly  sold  either  as  a  white  powder,  or  in  transparent 


90  SODA    SALTS. 

crystals  which  lose  water  and  become  opaque  when  exposed 
to  air.  It  dissolves  easily  in  water,  and  the  solution  turns 
red  litmus  paper  blue.  When  heated  on  a  knife  or  a  slip  of 
glass,  it  melts  and  swells  up,  evolving  steam,  and  leaving  a 
white  porous  mass.  When  fused  in  the  blowpipe-flame  in  a 
loop  of  platinum  wire  (243)  it  forms  a  bead  of  glass  which 
remains  transparent  on  cooling.  The  boracic  acid  may  be 
detected  according  to  Table  H. 

Glass  of  Borax  or  vitrified  borax,  NaaO.2B2O8,  forms 
transparent  or  semi-transparent  glassy-masses,  which  are 
dissolved  slowly  even  by  boiling  water,  and  require  the  blow- 
pipe-flame to  effect  their  fusion. 

Silicate  of  Soda,  Na4SiO4,  or  Soluble  Glass  is  generally 
sold  as  a  grayish  gummy  solution,  which  behaves  in  the 
same  manner  as  the  solution  of  silicate  of  potash  (p.  85). 

Tungstate  of  Soda,  Na,2WO4.2Aq.,  is  commonly  sold  in 
opaque,  irregular  crystals,  which  dissolve  easily  in  water, 
yielding  an  alkaline  solution,  which  gives  a  white  precipitate 
of  tungstic  acid  on  adding  diluted  hydrochloric  acid;  if  a 
piece  of  zinc  be  placed  in  the  solution  to  which  an  excess  of 
hydrochloric  acid  has  been  added,  a  beautiful  blue  oxide  of 
tungsten  is  gradually  formed. 

Soda-soap  is  soluble  in  warm  water,  giving  a  solution 
which  turns  red  litmus  paper  blue,  and  gives  a  white  pre- 
cipitate of  stearic  acid  on  addition  of  hydrochloric  acid. 
When  this  precipitate  is  boiled  in  the  liquid,  it  collects  as  an 
oily  layer  upon  the  surface. 

81.  Examples  for  Practice  in  Table  F. — The  following 
substances  may  be  analyzed  for  practice  (10): — 


Chloride  of  ammonium 
Bicarbonate  of  potash 
Chloride  of  sodium 
Biborate  of  soda 


Carbonate  of  soda 
Carbonate  of  potash 
Sulphate  of  soda 
Nitrate  of  potash. 


TABLE    G. 


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EVAPORATION.       GAS    BURNERS. 


NOTES  TO  TABLES  G  AND  H. 

84.  To  evaporate  a  solution — Pour  the  solution  into  an 
evaporating  dish  (a,  fig.  30),  supported  on  the  ring  of  a 
retort-stand  (6),  and  applying  a  moderate  heat. 


FIG. 30. 


FIG.  31. 


Evaporation. 

If  the  residue  spurts  about  as  the  evaporation  draws  to  a 
close,  place  the  dish  upon  an  empty  metal  pot  (fig.  31)  to 
equalize  the  heat  over  its  under  surface,  and  let  it  remain 
there  till  thoroughly  dry. 

Gas-lamps  are  by  far  the  most  convenient  for  evaporating 
solutions. 

The  Argand  Burner  (fig.  32)  is  one  of  the  best  for  general 

Fia.  32. 


GAS    BURNERS. 


use.     It  should  be  made  so  that  by  unscrewing  the  burner, 
a  plain  jet  (fig.  33)  for  blowpipe   experiments  may  be  ob- 

FIG.  33. 


tained.  A  brass  chimney  (c,  fig.  32)  may  be  made  to  drop 
loosely  over  the  burner,  resting  upon  its  shoulder  (a),  so  as 
to  increase  the  temperature  for  some  operations.  It  is  also 
convenient  to  have  a  brass  ring  (6),  holding  a  piece  of  iron 
wire  gauze  (with  about  400  meshes  to  the  square  inch)  which 
may  be  dropped  over  the  chimney  (fig.  34),  and  the  gas 
lighted  above  it,  so  as  to  obtain  the  very  hot  smokeless  flame 
of  .the  mixture  of  gas  and  air.  It  is  not  advisable,  however, 
to  use  this  flame  for  small  evaporations,  since  it  overheats 
the  sides  of  the  dish  and  cracks  it. 


FIG.  34. 


FIG.  3-5. 


Gauze  burner. 


Bunsen's  burner. 


The  Bunsen's  burner  (fig.  35)  furnishes  a  very  hot  smoke- 
less flame,  produced  by  the  admixture  of  air  with  the 
gas.  A  burner  on  the  same  principle  may  be  extemporized 
with  a  glass  funnel  and  a  plain  gas-burner,  as  described  at 
(70). 

By  twisting  a  band  of  folded  paper  round  the  lower  part 


96  FLUORINE    DETECTED. 

of  the  Bunsen's  burner,  so  as  to  close  the  air-holes,  a  lumi- 
nous flame  fit  for  blowpipe  work  may  be  obtained.  Such 
an  arrangement  also  allows  the  burner  to  be  used  with  a 
smaller  supply  of  gas. 

FlQ  36  Where  gas  is  not  to  be  ob- 

tained,* a  spirit  lamp  (fig.  36) 
may  be  used  for  evaporation,  or 
even  a  common  candle-flame,  if 
the  dish  be  supported  at  some 
little  distance  above  the  flame 
so  that  it  may  not  be  smoked. 

85.   An  organic  substance  is 
a  substance  of  animal  or  vege- 
table   origin ;    such    substances 
commonly  carbonize  when  heated  (17). 

86.  Since  the  action  of  sulphuric  acid  upon  some  sub- 
stances is  very  violent,  care  is  requisite  in  this  experiment; 
the  test-tube  should  not  be  held  near  the  face,  and  a  small 
quantity  of  the  substance  should  be  employed. 

87.  Hydrochloric  and  hydrofluoric  acid   gases  are  per- 
fectly transparent  in  the  test-tube,  but  as  soon  as  they  escape 
into  the  air,  they  attract  particles  of  moisture,  in  company 
with  which  they  condense  into  clouds.     Hydrobromic  and 
hydriodic  acid  gases  also  yield  clouds  in  moist  air,  but  they 
are  generally  accompanied  by  the  brown  vapor  of  bromine 
or  the  violet  vapor  of  iodine. 

88.  The  presence  of  fluorine  in  a  substance  (giving  rise 
to  the  evolution  of  hydrofluoric  acid)  may  be  confirmed  by 
placing  a  little  of  it,  in  fine  powder,  upon  a  slip  of  glass, 
moistening  it  with  strong  sulphuric  acid,  and  warming  it 
gently  for  a  minute  or  two.    After  cooling,  the  slip  of  glass  is 
thoroughly  washed,  wiped  dry,  and  held  so  that  the  eye  may 
glance  over  its  polished  surface,  when  the  spot  previously 

*  A  very  convenient  supply  of  portable  gas  is  now  furnished  by 
Mr.    Orchard,    of    High   Street,    Kensington,    compressed   in   safe 

-n7rr>nfrV,t_^T.r,Ti    ^-trl  i'n/1  ova      oa/.li    ™n  t  a  i  ni  r,  cr   1*    nnltin   foot    r>f  rrac 


TEST    FOR    CHLORATES.  97 

occupied  by  the  substance  will  be  found  to  have  entirely  lost 
its  polish  if  fluorine  be  present. 

The  action  of  hydrofluoric  acid  upon  the  silica  contained 
in  glass,  results  in  the  formation  of  fluoride  of  silicon  gas, 
which  is  decomposed  when  brought  into  contact  with  water, 
depositing  opaque  silica. 

89.  If  fluorine  be  detected,  the  particular  form  in  which 
it  is  present  remains  to  be  decided. 

Uncombined  Fluorine,  F,  if  known  at  all,  exists  only  in 
the  state  of  gas. 

Hydrofluoric  Acid,  HF,  never  occurs  in  the  solid  state. 
The  commercial  acid  is  a  solution  in  water,  always  known 
by  its  pungent  odor  and  corrosive  action  on  glass. 

The  only  compounds  of  fluorine  which  are  at  all  common, 
are — 

Fluor-spar,  composed  of  fluorine  and  calcium. 

Kryolite,  which  contains  fluorine,  aluminium,  and  sodium. 

Fluor  Spar  or  Fluoride  of  Calcium  has  been  described 
at  (59). 

Kryolite,  Na3AlF6,  is  a  white  opaque  mineral,  generally  in 
rectangular  masses.  It  is  insoluble  in  water,  and  but  slightly 
attacked  by  hydrochloric  or  nitric  acid.  The  powdered  min- 
eral, moistened  with  hydrochloric  acid  and  exposed  on  a 
clean  platinum  wire  (74),  colors  the  flame  intensely  yellow. 

When  heated  with  strong  sulphuric  acid,  kryolite  is  dis- 
solved ;  if  the  solution  be  further  heated,  it  becomes  milky, 
but  the  milkiness  disappears,  if  the  acid  liquid,  after  cooling, 
is  mixed  with  much  water  and  boiled. 

90.  Solid  chlorates  become  yellow  or  red  when  moistened 
with  concentrated  sulphuric  acid,  and  slowly  evolve,  even  in 
the  cold,  a  yellow  gas  (chloric  peroxide)  resulting  from  the 
decomposition  of  the  chloric  acid,  and  having  a  very  pecu- 
liar odor. 

Great  care  is  necessary  in  applying  heat,  since  the  explo- 
sive decomposition  of  the  chloric  peroxide  sometimes  shat- 
ters the  tube. 


98  HYPOCHLORITES. 

A  solution  containing  a  chlorate  becomes  yellow  when 
heated  with  strong  hydrochloric  acid,  emitting  an  odor  re- 
sembling chlorine. 

Solution  of  a  chlorate  will  (if  free  from  chloride)  give  no 
precipitate  with  nitrate  of  silver  until  it  has  been  acidulated 
with  dilute  sulphuric  acid  and  allowed  to  remain  in  contact 
with  metallic  zinc  for  a  minute  or  two. 

Chloric  Acid,  HC1O3,  is  not  commonly  met  with.  It  is  a 
strongly  acid  liquid,  which  bleaches  test-papers,  and  evolves 
an  odor  of  chlorine,  especially  when  heated. 

The  only  chlorates  which  are  at  all  common,  are  those  of 
potash -and  baryta,  which  have  been  described  at  p.  82  and 
p.  70  respectively. 

91.  The  odor  of  chlorine  is  perceived  if  the  substance  un- 
der examination  is  common  saltpetre,  which  always  contains 
some  chloride.    See  Nitre  (p.  81)  and  Nitrate  of  Soda  (p.  88). 

The  compounds  of  hypochlorous  acid  also  evolve  chlorine 
when  heated  with  sulphuric  acid. 

Hypochlorous  Acid  itself  exists  either  as  a  yellow  explo- 
sive gas,  C120,  or  an  aqueous  solution,  HC1O(?),  of  strong 
chlorous  odor  and  great  bleaching  power. 

Solutions  of  the  hypochlorites  give  a  dark  brown  pre- 
cipitate of  binoxide  of  manganese  on  adding  sulphate  of 
manganese. 

The  only  hypochlorite  commonly  met  with  is  the  Hypo- 
chlorite of  Lime,  Ca2Clo,  which  occurs  in  the  solution  of 
Chloride  of  Lime  of  commerce,  described  at  p.  74. 

Hypochlorite  of  Soda,  NaCIO,  exists  in  the  Chloride  of 
Soda,  which  is  sold  only  in  solution,  and  is  described  at  p.  89. 

92.  To  be  sure  of  the  presence  of  iodine,  add  to  a  solu- 
tion of  the  substance  to  be  tested  a  few  drops  of  thin  starch 
(353)  and  a  little  concentrated  nitric  acid  ;  the  nitrous  acid 
present   in    this  will   liberate   the  iodine,  which  colors  the 
starch  blue. 

93.  Uncombined  Iodine,  I,  is  met  with  in  shining  black 
scales   which    have    a    peculiar  odor,  somewhat  resembling 


IIYDKOSULPIIURTC    ACID.       SULPHIDES.  99 

chlorine.     It  stains  the  fingers  brown,  and  is  converted  into 
a  splendid  violet  vapor  when  heated. 

The  only  iodides  likely  to  be  met  with  in  ordinary  analysis 
are  those  of  potassium  (77),  iron  (45),  lead  (14),  mercury 
(31),  and  arsemr  (35). 

94.  To  recognize  the  carbonic  acid  gas,  dip  a  glass  rod 
into    lime-water,  and  introduce  it,  with  the  clear  drop  of 
lime-water  suspended  from  it,  into  the  mouth  of  the  test- 
tube,  when  the  drop  will  immediately  become  coated  with  an 
opaque  film  of  carbonate  of  lime,  which  will  disappear  again 
if  exposed  for  some  time  to  the  action  of  the  gas. 

95.  UncomMned  Carbonic  Acid  is  met  with  in  ordinary 
analysis,  either  in  the  state  of  gas,  C02,  or  dissolved  in  water, 
H2C03(?),  and  may  be  recognized  by  its  faint  odor,  its  fee- 
bly reddening  blue  litmus  paper,  and  its  causing  a  milky 
precipitate  with  lime-water,  which  disappears  when  the  acid 
is  added  in  excess. 

The  carbonates  most  commonly  met  with  are  those  of  lime 
(G9),  soda  (80),  potash  (77),  ammonia  (75),  baryta  (65), 
magnesia  (9),  iron  (45),  zinc  (53),'Zead  (14),  and  copper 
(27). 

96.  To  be  sure  of  the  presence  of  hydrosulphuric  acid, 
spot  a  piece  of  filter-paper  with  solution  of  acetate  of  lead 
or  nitrate  of  silver,  which  will  be  blackened  when  exposed 
to  the  action  of  that  gas. 

97.  Hydrosulphuric    Acid,  H2S,  itself   is    met  with    in 
analysis,  either    in  the    form    of   gas    or    of   a    solution  in 
water,  which  smells  of  the  gas  and  blackens  acetate  of  lead 
and  nitrate  of  silver. 

Many  of  the  sulphides  evolve  hydrosulphuric  acid  when 
they  are  heated  with  hydrochloric  acid.  The  most  important 
are  those  of  iron  (45),  antimony  (39),  ammonium  (75),  lead 
(14),  zinc  (53),  potassium,  and  calcium. 

Sulphide  of  Potassium,  K28,  is  generally  in  brown  frag- 
ments, which  easily  become  moist  on  exposure  to  air,  and 

smell  strono-lv  of  hvflro.milnhnrip  juMrL      Tt  dissolves  pnsilv  in 


100  PRUSSIAN    BLUE    TEST. 

water,  and  the  solution  generally  becomes  milky  when  mixed 
with  hydrochloric  acid,  from  the  deposition  of  a  little  sul- 
phur, due  to  the  presence  either  of  bisulphide  of  potassium 
or  of  hyposulphite  of  potash. 

Sulphide  of  Calcium,  CaS,  occurs  in  the  soda-waste  of  the 
alkali-works,  as  a  nearly  black  substance,  partly  dissolved  by 
boiling  water,  yielding  an  alkaline  solution.  Dilute  hydro- 
chloric acid  does  not  entirely  dissolve  it,  but  leaves  a  dark 
residue  containing  carbonaceous  particles. 

Ultramarine  is  a  blue  powder  which  becomes  white  and 
evolves  hydrosulphuric  acid  when  heated  with  hydrochloric 
acid.  It  contains  alumina,  silica,  sulphur,  sodium,  and  iron. 

98.  To  acquire  familiarity  with  the  odor  of  hydrocyanic 
(prussic)  acid,  heat  a  little  solution  of  ferrocyanide  of  potas- 
sium (yellow  prussiate  of  potash)  with  dilute  sulphuric  acid, 
when  pure  hydrocyanic  acid  will  be  evolved. 

In  order  to  be  sure  of  the  presence  of  hydrocyanic  acid, 
add  to  a  solution  of  the  substance  a  few  drops  of  solution  of 
sulphate  of  iron  and  a  slight  excess  of  potash  ;  shake  the 
precipitate  for  a  few  moments  with  the  air  in  the  tube,*  and 
add  an  excess  of  hydrochloric  acid,  when  a  blue  precipi- 
tate, or  a  decided  blue  or  green  color,  pervading  the  liquid, 
will  indicate  the  presence  of  hydrocyanic  acid,  or  of  a  cya- 
nide. 

In  this  test,  the  ferrous  oxide  and  the  potash,  acting  upon 
the  hydrocyanic  acid,  produce  ferrocyanide  of  potassium  ; 
when  the  hydrochloric  acid  is  added,  it  dissolves  the  ferric 
oxide  produced  by  the  action  of  the  air,  and  the  ferric 
chloride  so  produced,  coming  into  contact  with  the  ferro- 
cyanide of  potassium,  produces  ferrocyanide  of  iron  or  Prus- 
sian blue. 

If  the  cyanogen  were  originally  present  as  a  ferrocyanide 
or  a  ferridcyanide,  the  sulphate  of  iron  would  at  once  produce, 

*  A  drop  or  two  of  perchloride  of  iron  (ferric  chloride)  will  answer 
the  same  purpose  as  shaking  with  air. 


FULMINATE  OF  MERCURY.  101 

in  the  former  case,  a  comparatively  light  blue  precipitate,  in 
the  latter,  a  dark  blue. 

99.  Hydrocyanic  Acid  itself,  HCN,  is  met  with  in  aque- 
ous solution  only,  recognizable  by  its  odor,  its  very  faintly 
reddening;  blue  litmus  paper,  and  by  the  above  test. 

The  principal  compounds  of  cyanogen,  which  evolve  the 
odor  of  hydrocyanic  acid  when  they  are  heated  with  hydro- 
chloric acid,  are  cyanide  of  potassium  (77),  ferrocyanide 
(77),  and  ferridcyanide  (77)  of  potassium,  sulphocyanide  of 
potassium,  cyanide  of  mercury  (31),  fulminate  of  mercury. 

Sulphocyanide  of  Potassium,  KCNS,  forms  white  needle- 
like  crystals,  which  become  moist  in  the  air  and  dissolve 
very  easily  in  water.  Perchloride  of  iron  added  to  the 
solution  gives  a  deep  blood-red  color.  Heated  with  hydro- 
chloric acid,  the  sulphocyanide  deposits  a  yellow  precipitate, 
and  evolves  a  peculiar  offensive  gas  which  burns  with  a  blue 
flame. 

Fulminate  of  Mercury,  HgC2N2O2,  is  met  with  as  a  grayish 
crystalline  powder  which  is  easily  exploded  by  friction  or 
percussion.  If  placed  on  a  slip  of  ghiss  and  touched  with  a 
lighted  match,  it  burns  rapidly  with  a  bright  flash,  and  coats 
the  glass  with  metallic  mercury.  It  is  sparingly  dissolved 
by  boiling  water,  but  is  readily  soluble  in  hydrochloric  acid. 

Cyanide  of  Mercury  has  been  already  noticed  at  (31). 

Since  potash  does  not  decompose  the  cyanide  of  mercury, 
it  is  necessary,  before  applying  the  Prussian  blue  test  de- 
scribed above,  to  separate  the  mercury  by  slightly  acidulating 
the  solution  with  hydrochloric  acid,  and  introducing  a  piece 
of  zinc ;  in  the  course  of  a  few  minutes  the  solution  may  be 
poured  off  and  tested  with  sulphate  of  iron,  potash,  and 
hydrochloric  acid,  as  above  directed. 

100.  If  there  be  any  doubt  whether  the  odor  is  that  of 
sulphurous  acid,  place  a  piece  of  zinc  in  the  acid  liquid,  when 
the  hydrogen  which  is  disengaged  by  its  action  upon  the 
hydrochloric  acid  will  convert  the  sulphurous   into  hydro- 
sulnhuric  acid,  which  mav  be  re^o^nized  bv  its  odor  and  bv 


102  -SULPHURIC    ACID. 

its  blackening  paper  spotted  with  solution  of  acetate  of  lead 
or  nitrate  of  silver. 

Sulphurous  Acid  itself  is  met  with  either  as  a  gas,  S0a, 
or  a  solution  in  water,  H2S03(?),  always  recognizable  by  its 
odor.  The  principal  commercial  salt  of  sulphurous  acid, 
the  sulphite  of  soda,  has  been  described  at  p.  89. 

Hypo  sulphurous  Acid  is  not  known  to  exist  in  an  uncom- 
bined  state.  Its  only  common  form  of  combination,  the 
hyposulphite  of  soda,  has  been  described  at  p.  89. 

101.  Small  quantities  of  sulphuric  acid  (in  the  form  of 
sulphates)  are  very  commonly  found  as  an  impurity  in  com- 
mercial salts,  so  that  if  this  precipitate  be  scanty,  the  analyst 
must  hesitate  before  pronouncing  sulphuric  acid  to  be  an 
essential  constituent  of  the  salt.     Sulphuric  acid  will  also  be 
detected  in  a  solution  which  has  been  made  with  nitric  acid, 
whether  the  sulphur  existed  in  the  original  substance  as  a 
sulphide,  sulphite,  hyposulphite,  or  sulphate. 

102.  Sulphuric  Acid  itself  (sulphuric  anhydride,  S03), 
is    not    commonly  met  with,   except  in  combination   with 
water. 

Hydrated  Sulphuric  Acid  or  Oil  of  Vitriol,  H2SO4,  is  a 
heavy,  oily  liquid  which  has  usually  a  brownish  color  due 
to  the  presence  of  organic  matter.  If  it  be  poured  into  a 
little  water  in  a  test-tube,  much  heat  is  developed. 

The  Nordhausen  or  Saxon  Sulphuric  Acid  emits  fumes 
when  the  bottle  is  opened,  and  hisses  slightly  when  poured 
into  water. 

Diluted  Sulphuric  Acid  strongly  reddens  blue  litmus 
paper.  If  a  piece  of  white  paper  be  moistened  with  it,  and 
dried  at  a  gentle  heat,  it  assumes  an  intensely  black  color, 
the  paper  being  carbonized  by  the  acid. 

The  numerous  salts  of  sulphuric  acid  or  sulphates  have 
been  described  in  the  notes  referring  to  their  respective 
metals. 

102or.  A  white  precipitate  by  nitrate  of  baryta,  soluble 
in  dilute  nitric  acid,  indicates  either  carbonic  acid  (when 


SILVER    PRECIPITATES.  103 

the  precipitate  would  effervesce  with  the  acid),  phosphoric, 
oxalic,  boracic,  silicic,  sulphurous,  or  hyposulphurous  acid. 
These  will  all  be  detected  in  the  subsequent  part  of 
Table  H. 

103.  If  possible,  the  precipitate  produced  by  nitrate  of 
silver  should  be  allowed  to  settle,  and  the  liquid  should  be 
poured  off  before  boiling  the  precipitate  with  nitric  acid. 

Cold  nitric  acid  dissolves  all  the  common  precipitates  pro- 
duced by  nitrate  of  silver,  except  the  chloride,  sulphide,  and 
cyanide,  the  two  latter  requiring  to  be  boiled  with  the  acid. 

Cyanide  of  silver,  when  washed  (1C),  is  dissolved  by  heat- 
ing with  solution  of  potash,  which  converts  chloride  of  silver 
into  the  brown  oxide  of  silver,  but  does  not  dissolve  it. 

Several  other  less  common  silver  precipitates,  however, 
are  also  insoluble  in  nitric  acid,  such  as  iodide  (yellow),  bro- 
mide, ferrocyanide,  ferridcyanide  (brown  red),  and  sulpho- 
cyanide  of  silver. 

If  the  washed  silver  precipitate  be  shaken  with  ammonia, 
the  iodide  (whitened  by  the  ammonia)  and  ferrocyanide  are 
undissolved,  whilst  the  others  are  dissolved  by  ammonia. 

104.  Since  chlorides  are  commonly  found  as  impurities 
in  commercial  salts,  and  small  quantities  give  a  comparatively 
large  precipitate  with  nitrate  of  silver,  great  care  is  requisite 
before  concluding  that  the  substance  under  examination  is 
really  a  chloride. 

The  presence  of  a  chloride  may  be  confirmed  by  heating 
the  original  substance  with  dilute  sulphuric  acid  and  black 
oxide  of  manganese,  when  chlorine  gas  will  be  evolved,  which 
may  be  recognized  by  its  odor  and  by  its  bleaching  moistened 
litmus  paper.* 

Bromides  would  evolve  brown  vapors  of  bromine  having 

*  Corrosive  sublimate  (mercuric  chloride)  evolves  very  little 
chlorine  when  heated  with  diluted  sulphuric  acid  and  black  oxide 
of  manganese,  and  does  not  evolve  hydrochloric  acid  when  heated 
with  strong  sulphuric  acid. 


104  CHLORIDES.       SILVER    PRECIPITATES. 

an  intolerable  odor  and  imparting  an  orange  color  to  moist 
starch. 

Iodides  would  give  violet  vapors  of  iodine  turning  moist 
starch  blue. 

105.  Uncombined   Hydrochloric  Acid,  HC1,  is  usually 
met  with  in  a  state  of  solution  in  water.      Concentrated  hy- 
drochloric acid,  if  pure,  is  colorless,  but  the  common  acid 
has  a  yellow  color  due  to  iron.     It  fumes  strongly  in  damp 
air,  and  has  a  peculiar  suffocating  odor.     When  heated  with 
black  oxide  of  manganese,  it  evolves  abundance  of  chlorine, 
distinguished  by  its  irritating  odor  and  its  powerful  bleach- 
ing effect  upon  moist  litmus  paper.     Diluted  hydrochloric 
acid  does  not  fume  in  air,  but  also  evolves  chlorine  when 
heated  with  black  oxide  of  manganese. 

The  Chlorides,  which  are  precipitated  by  nitrate  of  silver 
just  as  hydrochloric  acid  would  be,  have  been  noticed  under 
their  respective  metals. 

106.  For  a  test  to  confirm  the  presence  of  hydriodic  acid, 
see  (92). 

Hydriodic  Acid,  HI,  in  the  free  state  is  not  commonly 
met  with.  The  Iodides,  which  behave  with  nitrate  of  silver 
just  like  hydriodic  acid,  have  been  described,  when  of  suffi- 
cient importance,  under  their  respective  metals. 

106«.  A  black  precipitate  produced  by  nitrate  of  silver 
indicates  hydrosulphuric  acid  (97).  A  white  precipitate 
rapidly  changing  to  orange  brown  and  black  indicates  hypo- 
sulphurous  acid.  See  hyposulphite  of  soda  (80).  A  brown 
precipitate  soluble  in  nitric  acid  may  be  arseniate  of  silver, 
indicating  arsenic  acid  (35),  or  oxide  of  silver,  indicating 
the  presence  of  some  caustic  alkaline  substance,  such  as  pot- 
ash, soda,  or  lime,  dissolved  in  water  (69,  77,  80). 

A  brown  or  red-brown  precipitate  insoluble  in  nitric  acid 
indicates  ferridcyanogen.  See  ferridcyanide  of  potassium  (77). 

A  white  precipitate  becoming  brown  or  black  when  heated, 
indicates  boracic  acid  (Table  H,  col.  6)  or  sulphurous  acid 
(100). 


NITRIC    ACID.  105 

A  white  precipitate  becoming  brown  when  heated  with 
nitric  acid,  and  then  dissolving  in  ammonia  which  failed  to 
dissolve  it  at  first,  is  ferrocyanide  of  silver  (113).  If  the 
nitrate  of  silver  be  not  in  excess,  a  blue  color  may  be  pro- 
duced by  the  nitric  acid.  A  red  precipitate  indicates  chromic 
acid  (1*20),  if  the  liquid  be  yellow  or  red,  or  arsenic  acid  if 
the  liquid  be  colorless.  In  both  cases  the  precipitate  is 
soluble  in  nitric  acid. 

107.  This  test  must  be  applied  to  a  cold  solution  ;  a  con- 
siderable quantity  of  sulphate  of  iron  is  necessary,  and  the 
sulphuric  acid  must  be  poured  slowly  in,  so  that  the  bulk  of 
it  may  sink  to  the  bottom  of  the  tube,  for  if  much  heat  be 
produced  by  its  mixing  with  the  water,  the  brown  compound 
indicative  of  nitric  acid  will  be  decomposed.     This  brown 
compound  contains  sulphate    of  iron,  in  combination  with 
nitric  oxide  which  has  been  formed  by  the  abstraction  of 
oxygen  from  the  nitric  acid,  in  order  to  convert  another  part 
of  the  sulphate  of  iron  (ferrous  sulphate)  into  the   persul- 
phate (ferric  sulphate). 

108.  If  additional  evidence  of  the  presence  of  nitric  acid 
be  required,  the   original    substance,  or  even  the  solution, 
when   cold,  may  be  mixed  with   about  an  equal  volume  of 
concentrated  sulphuric  acid,  a  few  copper  filings  or  clippings 
added,  and  heat  applied,  when  brown  fumes  of  nitric  per- 
oxide will  be  produced  by  the  deoxidizing  effect  of  the  copper 
upon  the  nitric  acid  liberated  by  the  sulphuric  acid.* 

109.  Nitric  Acid  itself  (nitric  anhydride,  N2O5)  is  ex- 
tremely uncommon,  except  in  combination  with  water. 

Concentrated  Nitric  Acid,  HNO3,  when  perfectly  pure,  is 
colorless,  but  it  generally  has  a  yellow  color  caused  by  the 
presence  of  nitric  peroxide,  NO2.  It  fumes  in  air,  stains  the 

*  The  nitrites,  or  salts  of  nitrous  acid,  evolve  brown  vapors  when 
treated  with  sulphuric  acid  in  the  cold,  and  give  a  brown  solution 
with  sulphate  of  iron  and  diluted  sulphuric  acid. 


106  NITRIC    ACID. 

skin  yellow,  and  when  poured  upon  copper  or  zinc  causes 
violent  effervescence  and  disengagement  of  red  fumes. 

The  Nitrous  Acid  of  commerce  is  concentrated  nitric  acid 
containing  a  larger  proportion  of  nitric  peroxide  which  im- 
parts to  it  an  orange-red  color.  Some  specimens  of  strong 
nitric  acid  have  a  green  color,  caused  by  the  presence  of 
nitrous  acid. 

Diluted  Nitric  Acid  (Aqua  Fortis)  of  course  reddens  lit- 
mus very  strongly,  and  acts  upon  copper  or  zinc  in  the  same 
manner  as  the  concentrated  acid,  but  with  less  violence. 

The  salts  formed  by  nitric  acid,  or  nitrates,  have  been 
described,  when  important,  in  the  notes  relating  to  the 
individual  metals. 

110.  If   the  original  solution  be  neutral  (18),  it  is  not 
necessary  to  add  ammonia  and  acetic  acid,  but  if  it  be  acid 
to  test-paper,  the  free  acid  may  prevent  the  formation  of  a 
precipitate  with  perchloride  of  iron  or  with  chloride  of  cal- 
cium, so  that  it  must  be  neutralized   with   ammonia,  which 
may  be  added  till  the  liquid  smells  slightly  of  it,  even  after 
being  shaken  with  the  thumb  on  the  top  of  the  tube,  and 
turns  red  litmus  paper  blue ;  acetic  acid  may  be   added  till 
the  smell  of  ammonia  is  no  longer  perceptible  after  shaking, 
and  the  liquid  reddens  blue  litmus   paper.     The  solution  is 
then  examined  as  in  the  Table. 

Should  any  precipitate  remain  undissolved  after  acetic  acid 
has  been  added  in  excess,  it  is  probably  phosphate  of  iron 
(p.  109),  oxalate  of  lime  (58),  fluoride  of  calcium  (59), 
phosphate  of  alumina  (p.  109),  or  phosphate  of  lead  (p.  110). 

111.  A  single  drop  of  perchloride  of  iron  is  here  recom- 
mended, because  the  precipitate  of  phosphate  of  iron  (ferric 
phosphate)  is  soluble  in  an  excess  of  the  perchloride. 

If  a  solid  compound  containing  phosphoric  acid  is 
throughly  dried  by  heat,  and  strongly  heated  in  a  tube  (17) 
with  a  little  metallic  magnesium,  the  mass,  after  cooling, 
evolves  the  peculiar  fishy  odor  of  phosphoretted  hydrogen  on 
boiling  with  water. 


PHOSPHORIC    ACID.  107 

The  most  delicate  test  for  phosphoric  acid  is  molybdate  of 
ammonia,  which  produces,  in  the  solution  acidulated  with 
nitric  acid  (and  free  from  hydrochloric  acid),  especially  on 
heating,  a  yellow  precipitate  containing  phosphoric  and 
molybdic  acids,  and  ammonia. 

Care  must  be  taken  to  avoid  mistaking  arsenic  acid  for 
phosphoric  acid  (p.  46). 

Ilia.  A  solution  containing  arsenious  acid  combined 
with  an  alkali  would  also  give  a  yellow  precipitate  soluble 
in  nitric  acid,  on  addition  of  nitrate  of  silver,  but  the 
absence  of  arsenious  acid  has  been  previously  established 
(Table  A). 

112.  Phosphoric  Acid  itself  (phosphoric  anhydride,  PSO5) 
is  not  commonly  met  with,  because  it  cannot  be  exposed  to 
air  without  absorbing  moisture  and  liquefying  to  a  solution 
of  phosphoric  acid.  The  ordinary  solution  of  phosphoric 
acid  is  a  colorless  liquid  which  strongly  reddens  blue  litmus 
paper.  If  it  be  mixed  with  a  slight  excess  of  ammonia,  and 
with  a  solution  of  sulphate  of  magnesia  to  which  chloride  of 
ammonium  and  ammonia  have  been^  added,  a  white  granular 
precipitate  of  phosphate  of  magnesia  and  ammonia  is  pro- 
duced, the  formation  of  which  is  much  promoted  by  stirring 
the  liquid  (6). 

Glacial  Phosphoric  Acid  (or  metaphosphoric  acid,  HPO3) 
forms  transparent  colorless  masses  which  easily  absorb  water 
from  the  air.  It  dissolves  in  cold  water,  and  the  solution 
gives  a  white  precipitate  with  nitrate  of  silver.  If  the  solution 
of  the  acid  in  water  be  boiled  for  some  time,  it  is  no  longer 
precipitated  by  nitrate  of  silver,  unless  a  very  little  ammonia 
is  added,  when  it  gives  a  yellow  precipitate,  the  metaphos- 
phoric acid  having  been  converted  into  orthophosphoric  or 
tribasic  phosphoric  acid,  H3PO4,  by  boiling  with  water. 

Phosphoric  acid  might  be  found  in  a  solution  pre- 
pared with  nitric  acid,  as  a  result  of  the  oxidation  of  phos- 
phorus. 

Ordinary  {vitreous}  phosphorus  is  easily  recognized  by  its 


108  PHOSPHATES    IDENTIFIED. 

inflaming  when  rubbed  or  gently  heated,  when  it  burns  with 
a  bright  flame  emitting  thick  clouds  of  anhydrous  phosphoric 
acid. 

Amorphous  or  red  phosphorus  does  not  inflame  when 
rubbed,  and  requires  a  higher  temperature  to  inflame  it  than 
ordinary  phosphorus.  When  heated  in  a  small  tube  closed 
at  one  end  (17)  it  is  converted  into  vapor  which  condenses 
into  drops  of  ordinary  phosphorus  on  the  cool  sides  of  the 
tube. 

Phosphate  of  Soda  has  been  described  at  (p.  89). 

The  presence  of  phosphoric  acid  in  the  phosphate  of  soda 
may  be  confirmed  by  mixing  the  solution  with  ammonia,  and 
testing  with  the  mixture  of  sulphate  of  magnesia,  chloride  of 
ammonium,  and  ammonia. 

The  solution  of  phosphate  of  soda  gives,  with  nitrate  of 
baryta,  a  white  precipitate  which  is  dissolved  by  dilute  nitric 
acid. 

With  nitrate  of  silver,  it  gives  a  yellow  precipitate,  soluble 
in  nitric  acid. 

Arseniate  of  soda,  which  much  resembles  the  phosphate 
(p.  46),  gives  a  brown  precipitate  with  nitrate  of  silver. 

Phosphate  of  Soda  and  Ammonia,  NaNH4HPO4,  or  micro- 
cosmic  salt,  or  phosphorus  salt,  forms  colorless  crystals,  which 
dissolve  in  water,  yielding  a  solution  which  blues  red  litmus. 

With  nitrate  of  baryta  and  nitrate  of  silver,  the  solution 
behaves  like  phosphate  of  soda. 

With  sulphate  of  magnesia,  especially  on  stirring,  it  yields 
the  precipitate  of  phosphate  of  magnesia  and  ammonia. 

When  microcosmic  salt  is  heated  in  a  dry  tube  (17),  it 
fuses  easily,  boils,  evolves  much  steam  and  ammonia  (detected 
by  its  odor),  leaving  a  transparent  glass  of  metaphosphate 
of  soda. 

Phosphate  of  Lime  and  Superphosphate  of  Lime  have  been 
noticed  at  (56). 

To  confirm  the  indication  of  the  presence  of  phosphoric 
acid  in  these  salts,  their  solutions  may  be  mixed  with  acetate 


PHOSPHATES    IDENTIFIED.  109 

of  ammonia  (prepared  by  mixing  ammonia  with  a  slight  ex- 
cess of  acetic  acid),  and  oxalate  of  ammonia  added  as  long 
as  the  precipitate  of  oxalate  of  lime  is  increased.  The  solu- 
tion is  then  boiled,  filtered,  mixed  with  ammonia  in  slight 
excess,  and  tested  with  the  mixture  of  sulphate  of  magnesia 
with  chloride  of  ammonium  and  ammonia. 

If  phosphate  of  lime  be  made  into  a  paste  with  concen- 
trated sulphuric  acid,  and  exposed  on  a  platinum  wire,  in 
the  margin  of  a  flame  (70),  the  greenish  flame  of  phosphorus 
will  be  perceived  in  the  dark. 

Phosphate  of  Magnesia  and  Ammonia,  or  triple  phosphate, 
MgNH4PO4,  is  a  white  crystalline  powder,  which  is  insoluble 
in  water,  but  dissolves  easily  in  hydrochloric  acid.  If  the 
hydrochloric  solution  be  largely  diluted  with  water,  mixed 
with  ammonia  in  excess,  and  stirred  with  a  glass  rod,  the 
phosphate  is  repreeipitated  in  a  granular  form,  especially 
upon  the  lines  of  friction  made  by  the  glass  rod. 

The  phosphate  of  magnesia  and  ammonia  evolves  ammo- 
nia when  boiled  with  potash. 

Phosphate  of  Alumina,  A1PO4,  i.s  insoluble  in  water,  but 
dissolves  in  hydrochloric  acid.  Potash  precipitates  it  from 
this  solution,  but  an  excess  of  potash  redissolves  it.  Ammo- 
nia also  precipitates,  but  does  not  redissolve  it. 

If  the  solution  of  phosphate  of  alumina  in  hydrochloric 
acid  be  mixed  with  a  solution  of  tartaric  acid,  and  afterwards 
with  an  excess  of  ammonia,  the  solution  will  remain  clear, 
and  the  phosphoric  acid  may  be  detected  by  the  mixture  of 
sulphate  of  magnesia  with  chloride  of  ammonium  and  am- 
monia. 

With  strong  sulphuric  acid,  in  a  flame,  phosphate  of  alu- 
mina behaves  like  phosphate  of  lime. 

Phosphate  of  Iron,  FePO4,  is  insoluble  in  water,  but 
soluble  in  hydrochloric  acid,  giving  a  yellow  solution.  On 
mixing  this  with  acetate  of  ammonia  (prepared  by  mixing 
ammonia  with  a  slight  excess  of  acetic  acid),  the  phosphate 
of  iron  is  separated  as  a  white  precipitate. 


110  FERROCYANIDES    IDENTIFIED. 

If  the  hydrochloric  solution  of  the  phosphate  of  iron  be 
mixed  with  ammonia  in  excess,  a  brownish  precipitate  of 
basic  phosphate  of  iron  is  obtained  ;  by  boiling  this  with 
sulphide  of  ammonium,  the  iron  is  converted  into  (black) 
sulphide  of  iron,  and  the  phosphoric  acid  is  dissolved  as 
phosphate  of  ammonia,  and  may  be  detected  in  the  filtered 
solution  by  sulphate  of  magnesia,  mixed  with  chloride  of 
ammonium  and  ammonia. 

Phosphate  of  Lead  is  white,  insoluble  in  water,  and  not 
easily  soluble  in  hydrochloric  acid,  but  diluted  nitric  acid 
dissolves  it ;  ammonia  added  to  this  solution  precipitates  the 
phosphate  of  lead,  and  acetic  acid  does  not  redissolve  it. 

By  boiling  the  phosphate  of  lead  with  sulphide  of  ammo- 
nium, the  phosphoric  acid  is  converted  into  phosphate  of 
ammonia,  and  may  be  detected  in  the  filtered  solution,  with 
the  mixture  of  sulphate  of  magnesia  with  chloride  of  ammo- 
nium and  ammonia. 

113.  Ferrocyanogen  is  the  name  given  to  the  group 
C6N6Fe  containing  carbon,  nitrogen,  and  iron,  which  is  sup- 
posed to  exist  in  the  ferrocyanide  of  potassium,  and  in  other 
ferrocyanides,  though  it  has  never  been  obtained  in  the  sepa- 
rate state. 

Hydroferrocyanic  (or  ferrocyanic)  Acid,  H4C6N6Fe^  is 
not  at  all  a  common  substance.  It  is  crystalline,  and  easily 
soluble  in  water.  When  the  solution  is  boiled,  it  evolves 
the  odor  of  hydrocyanic  acid,  and  deposits  a  white  preci- 
pitate of  cyanide  of  iron,  which  rapidly  turns  blue  by 
oxidation. 

Ferrocyanide  of  Potassium  has  been  described  at  (p.  84). 
Its  solution  gives,  with  nitrate  of  silver,  a  nearly  white  pre- 
cipitate of  ferrocyanide  of  silver,  which  is  not  dissolved  by 
ammonia. 

If  this  precipitate  be  warmed  with  dilute  nitric  acid,  it  is 
converted  into  the  orange-red  ferridcyanide  of  silver,  and  is 
then  dissolved  by  ammonia,  with  exception  of  a  few  flakes 
of  peroxide  of  iron. 


TESTS    FOR    OXALIC    ACID.  Ill 

Sulphate  of  iron  causes  a  blue  precipitate  in  solution  of 
ferrocyanide  of  potassium. 

Ferrocyanide  of  Iron,  or  Prussian  Blue,  Fe&12CN,  is  not 
dissolved  by  water  or  dilute  acids.  It  may  be  identified  by 
boiling  it  with  potash,  which  leaves  brown  peroxide  of  iron 
undissolved,  and  yields  a  solution  of  ferrocyanide  of  potas- 
sium which  may  be  filtered,  neutralized  with  hydrochloric 
acid,  and  tested  with  perchloride  of  iron. 

Ferrocyanide  of  Copper,  or  Ifatchett's  Brown,  Cu2Fe6CN, 
has  a  brown-red  color,  and  is  insoluble  in  water,  and  in 
dilute  acids.  It  is  decomposed  by  boiling  with  potash,  into 
black  oxide  of  copper  and  ferrocyanide  of  potassium,  which 
may  be  tested  as  in  the  case  of  Prussian  blue. 

114.*  In  order  to  obtain  confirmatory  evidence  of  the 
presence  of  oxalic  acid,  shake  a  little  of  the  original  sub- 
stance with  diluted  sulphuric  acid  (which  does  not  cause 
effervescence  with  oxalic  acid),  and  throw  in  a  little  pow- 
dered binoxide  of  manganese,  when  carbolic  acid  will  escape 
with  effervescence,  especially  if  a  gentle  heat  be  applied,  and 
may  be  recognized  by  the  lime-water  test  (04). 

115.  Oxalic  Acid,  H2C2O4.2Aq.,  itself  forms  colorless 
prismatic  crystals,  which  dissolve  easily  in  water,  and  yield 
a  strongly  acid  solution. . 

When  heated  with  strong  sulphuric  acid,  oxalic  acid  dis- 
solves with  effervescence,  evolving  carbonic  acid  and  car- 
bonic oxide  gases,  the  latter  of  which  burns  with  a  blue  flame 
on  approaching  the  mouth  of  the  tube  to  a  flame. 

With  nitrate  of  baryta,  a  strong  solution  of  oxalic  acid 
gives,  on  stirring  with  a  glass  rod,  a  granular  precipitate  of 
oxalate  of  baryta,  which  dissolves  in  diluted  nitric  acid. 

With  nitrate  of  silver,  solution  of  oxalic  acid  gives  a  white 

*  Ferrocyanide  of  potassium  may  also  give,  with  chloride  of  cal- 
cium, a  precipitate  of  the  double  ferrocyanide  of  calcium  and  potas- 
sium, which  might  be  mistaken  for  oxalate  of  lime,  since  it  is  in- 
soluble in  acetic  acid,  but  soluble  in  hydrochloric  acid,  from  which 
ammonia  reprecipitates  it. 


112  BORACIC    ACID    IDENTIFIED. 

precipitate  of  oxalate  of  silver,  which  is  soluble  in  diluted 
nitric  acid. 

When  heated  in  a  dry  tube  (17),  oxalic  acid  melts  very 
easily,  and  is  entirely  converted  into  vapor,  a  part  of 
which  condenses  on  the  sides  of  the  tube  in  fine  transparent 
needles. 

The  Oxalates  commonly  met  with  are  the  acid  oxalate  of 
potash  (p.  85),  oxalate  of  ammonia  (75),  and  oxalate  of  lime 
(58). 

116.  This  test  for  boracic  acid  depends  upon  its  singular 
property  of  coloring  orange-red  the  dye  known  as  turmeric ; 
but  this  property  belongs  only  to  free  boracic  acid,  so  that  if 
it  be  combined  with  a  base,  it  is  necessary  to  liberate  it  by 
adding  hydrochloric  acid,  until  the  solution  reddens  blue  lit- 
mus paper.  A  large  excess  of  hydrochloric  acid  must  be 
avoided,  since  it  is  liable  to  carbonize  the  paper  on  drying. 

The  paper  may  be  dried  by  waving  it  above  the  flame  so 
as  not  to  scorch  it,  or  by  gently  warming  it  upon  a  slip  of 
glass. 

To  obtain  confirmatory  evidence  of  the  presence  of  boracic 
acid,  mix  the  substance  under  examination  with  strong  sul- 
phuric acid;  add  alcohol,  and  inflame  the  mixture,  either 
upon  a  glass  rod  dipped  into  it,  or  on  a  slip  of  glass,  or  in  a 
small  evaporating  dish,  in  the  latter  case  stirring  it  with  a 
glass  rod.  Boracic  acid  imparts  a  decided  green  color  to  the 
flame,  especially  at  the  edges. 

11*7.  Boracic  Acid  itself  (anhydrous  boracic  acid,  B203) 
is  not  commonly  met  with.  It  forms  glassy  fragments,  trans- 
parent when  freshly  prepared,  but  becoming  opaque  when 
kept.  It  is  powdered  with  great  difficulty,  and  appears  at 
first  to  be  insoluble  in  water  and  acids,  but  after  boiling  with 
water  for  a  short  time,  a  little  of  it  is  dissolved,  yielding  a 
solution  which  turns  blue  litmus  paper  violet,  and  stains 
turmeric  paper,  which  has  been  dipped  into  it  and  dried, 
orange-red,  becoming  green  when  moistened  with  potash. 

Glassy  boracic  acid  dissolves  easily  when  heated  with  potash. 


SILICIC    ACID    DETECTED.  113 

Crystallized  (or  hydrated)  Boracic  Acid,  3H2O.B2O3,  forms 
white  scaly  or  feathery  crystals,  which  dissolve  in  boiling 
water,  and  are  deposited  again  when  the  solution  cools.  The 
solution  behaves,  with  litmus  and  turmeric  papers,  as  stated 
above.  Placed  on  the  point  of  a  knife  or  on  a  platinum  wire 
(74),  and  heated  in  the  margin  of  a  flame  (70),  crystals  of 
boracic  acid  color  the  flame  green,  a  part  of  the  acid  being 
converted  into  vapor  in  the  presence  of  the  water.  The 
crystals  are  dissolved  by  boiling  alcohol,  and  the  solution 
burns  with  a  fine  green  flame. 

The  impure  boracic  acid  imported  from  Tuscany,  always 
contains  considerable  quantities  of  ammonia  and  sulphuric 
acid,  as  impurities. 

The  only  common  borates  are  Borax,  or  Biborate  of  Soda 
(p.  89),  and  the  mineral  Boronatrocalcite,  which  is  composed 
of  boracic  acid,  soda,  lime,  and  water,  and  is  imported  from 
Peru  under  the  name  of  Borate  of  Lime. 

Boronatrocalcite*  occurs  in  soft  earthy  masses  ;  it  is  dis- 
solved to  a  slight  extent  by  water,  and  entirely  by  hydro- 
chloric acid.  If  it  is  dissolved  in  a  small  quantity  of  hydro- 
chloric acid,  ammonia  will  cause  a  precipitate  of  borate  of 
lime;  but  if  much  acid  be  present,  the  chloride  of  ammonium 
formed  will  be  sufficient  to  prevent  the  precipitation,  since 
borate  of  lirne  is  soluble  in  chloride  of  ammonium. 

118.  To  detect  silicic  acid,  the  solution  which  has  been 
acidified  with  hydrochloric  acid  is  evaporated  to  dryness^ 
(i.  e.,  until  no  more  liquid  remains)  in  a  dish  (84) ;  the  latter 
is  allowed  to  cool,  and  some  diluted  hydrochloric  acid  poured 
into  it.  The  dish  is  again  gently  heated,  and  its  contents 
stirred  with  a  glass  rod ;  when  nothing  more  appears  to  dis- 
solve, the  contents  of  the  dish  are  poured  into  a  test-tube. 
If  silicic  acid  is  present,  semi-transparent  flakes  will  be 

*  Na20.2B2032(Ca0.2B203).lSAq. 

f  When  a  considerable  quantity  of  silicic  acid  is  present,  the 
liquid  becomes  a  jelly  at  a  certain  stage  of  the  evaporation. 


114  CHROMIC    ACID. 

seen  in  the  liquid,  giving  it  a  peculiar  opalescent  appear- 
ance. 

The  silicic  acid  may  be  filtered  off,  and  the  solution  testec\ 
for  potassium  and  sodium  according  to  Table  F,  p.  77. 

The  only  common  substance  which  is  likely  to  be  mistaken 
for  silicic  acid  in  this  test  is  sulphate  of  lime,  which  is  not 
immediately  redissolved  by  hydrochloric  acid  after  evapora- 
tion to  dryness,  though  continued  heating  with  the  acid  will 
dissolve  it.  But  the  sulphate  of  lime  is  more  opaque,  and  is 
generally  left  as  a  crystalline  powder,  which  sinks  much 
more  readily  than  the  silicic  acid.  Should  there  be  any 
doubt,  the  insoluble  part  may  be  allowed  to  settle  in  the 
tube,  washed  twice,  by  decantation  (16)  and  heated  with  a 
little  potash,  which  will  easily  dissolve  silicic  acid,  but  riot 
sulphate  of  lime. 

119.  The  common  forms  of  silicic  acid,  as  well  as  the 
more  frequently  occurring  silicates,  are  insoluble  in  water 
and  in  diluted  acids,  and  will  therefore  be  noticed  here- 
after. 

The  only  silicates  which  are  soluble  in  water  are  the 
Silicate  of  Potash  (p.  85),  and  Silicate  of  Soda  (p.  90). 
Even  those  silicates  which  are  attacked  by  boiling  with 
diluted  acid  (such  as  the  Zeolitic  minerals,  and  various 
slags),  do  not  generally  dissolve  in  the  acid,  but  leave  a 
residue  of  gelatinous  silicic  acid,  so  that  they  will  be  noticed 
together  with  substances  insoluble  in  water  and  acids. 

120.  Chromic  Acid  itself,  CrO3,  forms  needle-like  crys- 
tals of  a  crimson  color ;  they  attract  moisture  readily  from 
air,  and  dissolve  easily  in. water;  the  solution  gives  a  bright 
yellow  precipitate  with  acetate  of  lead,  and  a  red  precipitate 
with  nitrate  of  silver. 

The  chromates  most  commonly  met  with  are  chromate  of 
potash  (61),  bichromate  of  potash  (61),  chromate  of  baryta 
C65").  and  chromate  of  lead  (n.  %9}. 


EXAMPLES    FOR    PRACTICE. 


115 


121.    Examples  for  Practice  in  Tables  G  and  H. — The 
following  substances  may  be  analyzed  for  practice  (10)  : — 


Chalk  (carbonate  of  lime) 
Common  salt  (chloride  of  sodium) 
Fluor  spar  (fluoride  of  calcium) 
Chloride  of  lime 
Sulphide  of  iron 
Ferroeyanide  of  potassium 
Hyposulphite  of  soda 
Phosphate  ot  soda 


Oxalic  acid 

Saltpetre  (nitrate  of  potash) 
Chlorate  of  potash 
Iodide  of  potassium 
Cyanide  of  potassium 
Sulphite  of  soda 
Sulphate  of  magnesia 
Borax  (biborate  of  soda) 


Silicate  of  potash. 


116 


TABLE    I. 


§ 

13 
ti 

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P- 

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^^    »«< 

SSflS 

«.=g 

^5^ 


li  I  jfjiii 


"3  ?H       "S        ®     «    -2    « 
-«      I      -S^H=- 

§  02         I     *     O 


S3 


»**^1 


. 

25),  on  a  p 
minutes  (1 
warm  wat 


3        rfB 


0  o 


03 

•s 


1.2     l£  S 


. 
•&*  .  Sp«;s*^^-f|^x^s£|S)  .i^I'Sx 

f  &      ^'S  •  1  2      I  -S5  B  •«     S  fe  o  3  o     J~  2  -J--^ 

-go      |^2^    to§»|-g     °|^|S     ^S-g1" 

fcC  ^  S  sc    IT?  to  en 


HEATING    ON    PLATINUM    FOIL. 


117 


EXPLANATIONS  AND  INSTRUCTIONS  ON 
TABLE  I. 

123.  Mode  of  observing  the  action  of  heat  upon  substances 
in  contact  with  air. — A  small  piece  of  platinum  foil  is  very 
convenient  for  this  purpose. 

It  may  be  held  in  a  pair  of  crucible  tongs  (fig.  37),  or 
upon  a  triangle  of  iron  wire  (fig.  38),  one  limb  of  which  is 
thrust  through  a  cork  for  convenience  in  holding  it  when 
hot. 

Fia.  38. 


FIG.  37. 


Crucible  Tougs. 


Triangle. 

The  substance  under  examination  should  be  placed  at  one 
corner  of  the  foil,  so  that  the  latter  may  not  be  rendered 
entirely  useless  if  the  substance  should  corrode  it. 

A  gentle  heat  should  be 
applied  at  first  by  holding 
the  foil  a  little  above  the 
point  of  a  flame.  A  stronger 
heat  may  be  afterwards  ob- 
tained by  directing  the  blow- 
pipe-flame upon  the  under 
surface  of  the  foil  (fig.  39). 

Compounds    of    lead,    bis- 
muth, tin,  antimony,  and  arsenic  should  not  be  heated  on 
platinum  foil,  since  these  substances  corrode  it. 


FIG.  39. 


118 


PULVERIZATION. 


FIG.  40. 


.  A  piece  of  broken  porcelain,  or  a  small  porcelain  crucible, 
may  be  used  instead  of  platinum  foil. 

A  small  piece  of  thin  Ger- 
man glass  tube  open  at  both 
ends  will  answer  the  same 
purpose,  especially  if  it  be 
slightly  bent  so  that  the  sub- 
stance may  rest  in  it.  The 
tube  should  be  so  held  that 
one  opening  is  considerably 
higher  than  the  other,  and  to 
this  higher  opening  the  nose  should  be  applied,  in  order  to 
detect  the  odor  of  sulphur,  arsenic,  &c.  (fig.  40). 

124.  Reduction  of  substances  to  powder. — Most  substan- 
ces can  be  crushed  and  afterwards  ground  to  powder  in  a 
pestle  and  mortar  (fig.  41)  of  Wedgwood  ware.  A  small  spa- 
tula (fig.  42)  is  used  to  scrape  the  powder  out  of  the  mortar. 


FIG.  41. 


FIG.  42. 


Large  fragments  must  first  be  broken  up  by  the  hammer 
on  an  anvil. 


FIG.  43. 


An  iron  pestle  and  mortar  are  very  con- 
venient for  crushing  hard  substances. 

To  prevent  fragments  of  the  substance 
from  flying  about,  a  wooden  cover  (fig.  43) 
should  be  placed  over  it,  with  a  hole  for 
the  handle  of  the  pestle. 

When  the  mortar  is  not  at  hand,  sub- 
stances of  moderate  hardness  may  be  pow- 


POWDERING.       SIFTING. 


119 


dered   on   a    hard   surface    by  rolling  a  thick   bottle   over 
them. 

An  agate  mortar  and  pestle  (fig.  44)  are  used  for  the  final 
grinding  of  very  hard  substances.  The  agate  pestle  should 
be  provided  with  a  handle  made  of  hard  wood,  and  fitted  to 
it  by  a  brass  cap  (fig.  45).  The  powdering  is  very  much 


FIG.  44. 


facilitated  by  mounting  the  pestle  on  a  brass  rod,  which  plays 
in  a  ring  attached  to  a  stout  wooden  upright  rising  from  a 
heavy  bed  of  hard  wood  in  which  the  agate  mortar  is  firmly 
set  (fig.  46). 

Reduction    of    substances    to  FIG.  47. 

powder  is  sometimes  hastened 
if  the  fragments  are  sifted  out 
from  time  to  time,  by  rubbing 
the  powder  lightly  with  the  fin- 
ger upon  a  piece  of  muslin  tightly 
stretched  over  the  mouth  of  a 
beaker  (fig.  47 ) .  The  fragments 
left  on  the  muslin  are  returned 
to  the  mortar. 

For  powdering  small  quantities  of  very  hard  substances,  a 


120 


FUSION    ON    PLATINUM    FOIL. 


steel  diamond  mortar  (fig.  48)  is  employed,  consisting  of  a 
socket  (a  fig.  49),  into  which  a  steel  cylinder  open  at  both 
ends  (b)  fits  tightly.  The  substance  to  be  powdered,  in 
small  fragments,  is  dropped  into  the  hollow  cylinder,  and  the 
solid  steel  cylinder  (c)  which  fits  the  former  exactly,  being 
placed  upon  it,  it  is  struck  sharply  and  repeatedly  with  a 
heavy  hammer. 


FIG.  48. 


Fia.  49. 


125.  Fusion  of  insoluble  substances  with  carbonate  of 
soda. — The  substance  should  be  reduced  to  an  impalpable 
powder,  that  is,  to  a  powder  in  which  no  grit  can  be  felt 
(124),  and  intimately  mixed  with  the  carbonate  of  soda,  also 
in  fine  powder,  either  in  a  small  mortar  (fig.  41)  or  with  a 
knife  upon  a  piece  of  paper. 

The  carbonate  of  soda  employed  for  this  fusion  must  have 
been  previously  dried  to  expel  its  water  of  crystallization. 
The  fusion  is  easier  when  a  mixture  of  carbonates  of  soda 
and  potash  is  employed. 

The  mixture  is  placed  upon  a  piece 
of  platinum  foil,*  slightly  bent  up  at 
the  edges  (fig.  50),  and  heated  mode- 
rately at  first  to  expel  any  moisture 
which  may  be  present.  The  foil  is 
then  heated  to  redness,  over  a  Bunsen 
(fig.  51)  or  gauze  (fig.  52)  burner,  or  by 
directing  a  broad  blowpipe-flame  upon 


FIG.  50. 


*  A  piece  of  foil  1^  in.  long  and  l'£  in.  wide,  of  such  thickness  as 
to  weigh  seven  grains,  will  be  found  suitable  for  the  purpose. 


INSOLUBLE  SUBSTANCES.  121 

its  under  surface  (fig.  39).*  To  obtain  such  a  flame,  the 
blowpipe  jet  should  be  held  a  little  away  from  the  flame,  so 
that  a  broad  divergent  stream  of  air  may  be  sent  through  it. 

FIG.  51.  Fia.  52. 


Gauze  burner.  Bunsen's  burner. 

Since  only  a  small  quantity  of  the  powder  can  be  fused  at 
once  upon  the  foil,  it  is  advisable  to  add  it  in  successive  por- 
tions, as  each  is  melted,  until  a  sufficient  quantity  of  the  sub- 
stance has  been  employed. 

When  the  mixture  is  very  difficult  to  fuse,  the  blowpipe 
flame  must  be  directed  down  upon  its  surface  after  the  lower 
part  has  been  fused.  No  violence  must  be  employed  to 
detach  the  fused  mass  from  the  foil,  but  it  should  be  soaked 
in  water  as  directed  at  (131). 

A  small  platinum  capsule  (fig.  53)  is  very  con- 
venient for  the  fusion  of  insoluble  substances. 


NOTES  TO  TABLE  I. 

125ft.  A  substance  insoluble  in  water  and  acids  will 
most  likely  be  one  of  the  following: — carbon,  sulphur,  silica, 
silicate  of  alumina  (clay),  fluoride  of  calcium,  sulphate  of 

*  It  is  better  to  support  the  platinum  foil  upon  the  triangle  (fig. 
38)  than  to  hold  it  with  the  tongs,  which  generally  contaminate 
the  substance  with  iron. 
11 


122  SULPHUR.       CARBON. 

baryta,  sulphate  of  lime,  binoxide  of  tin,  chloride  of  silver, 
sulphate  of  lead  or  chrome-iron-ore. 

126.   Sulphur  is  likely  to  be  met  with  in  several  forms. 

Crude  Sulphur,  as  imported  from  Sicily  and  elsewhere, 
forms  grayish  yellow  lumps,  and  leaves  a  slight  dark  residue 
when  burnt. 

Distilled  Sulphur,  used  for  the  manufacture  of  gunpowder, 
forms  pure  yellow  lumps,  and  burns  without  residue. 

Roll  Sulphur  (common  brimstone)  forms  pure  yellow 
cylindrical  sticks,  also  burning  without  residue. 

These  three  varieties  dissolve  entirely,  or  nearly  so,  in 
bisulphide  of  carbon. 

flowers  of  Sulphur  (or  sublimed  sulphur)  is  a  fine  yellow 
powder,  which  burns  without  residue,  but  is  not  entirely 
dissolved  by  the  bisulphide  of  carbon,  since  it  contains 
a  considerable  proportion  of  the  insoluble  variety  of 
sulphur. 

Milk  of  Sulphur  (or  precipitated  sulphur}  is  a  white  im- 
palpable powder  which  generally  leaves  a  considerable  white 
residue  (sulphate  of  lime)  when  burnt. 

Viscous  Sulphur,  obtained  by  pouring  hot  melted  sulphur 
into  water,  has  a  brown  color,  and  somewhat  resembles 
India-rubber;  it  becomes  brittle  when  kept  for  a  few  hours. 
Sulphur  sometimes  separates  in  viscous  masses  when  the 
sulphides  of  the  metals  are  dissolved  in  nitric  acid. 

12*7.  Carbon  is  met  with  in  the  forms  of  diamond, 
graphite,  vegetable  charcoal,  animal  charcoal,  coal,  coke, 
gas-carbon,  lamp-black,  soot. 

Diamond  is  generally  recognized  by  its  extreme  hardness, 
rendering  it  capable  of  scratching  glass  and  even  steel.  It  is 
unaffected  when  heated,  in  a  small  leaden  or  platinum  cup, 
with  hydrofluoric  acid,  or  a  mixture  of  sulphuric  acid  arid 
ammonium  fluoride,  which  would  dissolve  the  imitations  of 
diamond.  It  burns  with  difficulty  in  air,  even  when  heated 
in  the  blowpipe-flame,  arid  is  best  recognized  by  burning  it  in 
oxygen,  and  detecting  the  carbonic  acid  produced,  by  means 


VARIETIES    OF    CARBON.  123 

of  lime-water.  The  mode  of  effecting  the  combustion 
of  the  diamond  is  described  in  most  works  on  Elementary 
Chemistry. 

Graphite,  plumbago,  or  black  lead  is  recognized  by  its 
semi-metallic  lustre,  especially  when  rubbed  with  a  hard  sub- 
stance, and  by  its  greasy  feeling  between  the  fingers.  It 
burns  away  very  slowly  when  heated  in  air,  and  generally 
leaves  a  considerable  residue  of  (brown)  peroxide  of  iron. 

Vegetable  Charcoal  (wood  charcoal)  may  of  course  gene- 
rally be  recognized  by  its  appearance.  It  glows  readily 
when  heated  in  air,  and  leaves  a  small  quantity  of  white 
very  light  ash. 

Animal  Charcoal  (bone-black,  ivory-black,  char)  burns 
pretty  easily  when  strongly  heated,  but  leaves  a  very  large 
earthy  residue  (phosphate  and  carbonate  of  lime).  This 
variety  of  charcoal  effervesces  slightly  with  hydrochloric  acid, 
which  dissolves  the  phosphate  and  carbonate  of  lime,  the 
former  being  deposited  as  a  white  gelatinous  precipitate  on 
mixing  the  filtered  solution  with  ammonia  in  excess. 

Coal  evolves  a  tarry  odor  when  heated,  and  furnishes  a 
coke  which  burns  away  with  some  (Tifficulty,  leaving  a  mode- 
rate ash  consisting  chiefly  of  silica  and  alumina,  but  having 
a  reddish-brown  color  (due  to  peroxide  of  iron)  if  much 
iron-pyrites  be  present  in  the  coal. 

Coke  of  course  behaves  in  the  same  way,  but  does  not 
evolve  tarry  odors.  Both  coal  and  coke  burn  vividly  (defla- 
grate) when  thrown  into  melted  nitre  heated  to  redness. 

Gas-carbon  (the  deposit  which  lines  the  interior  of  gas- 
retorts)  somewhat  resembles  coke  in  appearance,  but  is  much 
harder  and  more  compact,  having  almost  a  metallic  sound 
when  struck.  It  is  very  difficult  to  burn  it  in  air,  and  a 
high  temperature  is  required  to  deflagrate  it  with  nitre. 

Lamp-black  (spirit -block)  is  known  by  its  dead  black  ap- 
pearance and  great  lightness.  It  glows  easily  when  heated 
in  air,  and  burns  entirely  away  when  pure,  but  commercial 
lamp-black  often  leaves  a  considerable  white  ash. 


124 


INSOLUBLE    SUBSTANCES. 


Soot  may  be  recognized  by  its  odor.  It  burns  easily  in 
air.  When  boiled  with  solution  of  potash,  it  evolves  an 
odor  of  ammonia,  derived  from  the  destructive  distillation  of 
the  coal. 

128.  Chloride  of  Silver,  AgCl,  dissolves  when   heated 
with  ammonia  ;  if  an  excess  of  nitric  acid  be  added  to  the 
solution,  white  chloride  of  silver  is  reprecipitated,  and  be- 
comes violet  when  exposed  to  daylight. 

Chloride  of  silver  also  dissolves  in  solution  of  hyposulphite 
of  soda. 

129.  The  presence  of  fluor-spar  may  be  confirmed  accord- 
ing to  (59). 

130.  Should  the  fused  mass  have  a  bright  yellow  color,  it 
is  due  to  the  formation  of  an  alkaline  chromate,  and  indicates 
the  presence  of  chromium.     A  dark  green  color,  changing 
to  turquoise  blue  on  cooling,  is  caused  by  manganate  of  soda, 
and  indicates  the  presence  of  manganese. 

131.  The   platinum  foil  with   the  fused  mass  should  be 

placed,  as  soon  as  the  mass  has 
set,  in  an  evaporating  dish  (fig.  54) 
containing  about  half  an  ounce 
(four  teaspoonfuls)  of  distilled  wa- 
ter. The  dish  is  gently  heated, 
and  the  surface  of  the  foil  lightly 
rubbed  under  the  water,  with  a 
glass  rod  rounded  at  the  end, 
until  the  mass  has  become  de- 
tached. The  foil  is  then  re- 
moved, and  the  mass  stirred  with 
the  water,  and  crushed  under 
the  glass  rod  until  it  is  entirely 
disintegrated  ;  the  insoluble  resi- 
due is  then  collected  on  a  filter. 

132.  Since  the  carbonate  of  soda  (which   lias  been  used 
in  the  fusion)  is  liable  to  contain  sulphuric  acid  as  an  impu- 
rity, it  is  advisable  to  test  it  for  that  acid  before  concluding 


FIG.  54. 


Evaporation. 


TIN    STONE.  125 

that  the  sulphuric  acid  here  detected  really  belongs  to  the 
substance. 

If  the  sulphuric  acid  be  really  present  as  an  essential  con- 
stituent of  the  substance  insoluble  in  water  and  acids,  it  must 
exist  in  the  form  of  sulphate  of  baryta,  sulphate  of  strontia, 
sulphate  of  lime,  or  sulphate  of  lead. 

133.  Sulphate  of  Baryta,  BaSO4,  or  heavy-spar  (some- 
times called  barytes  or  cawk)  occurs  naturally  in  a  transparent 
colorless  form,  crystallized  in  prisms.     It  is  more  commonly 
opaque,  and  of  a  brownish  color.     By  a  skilful  operator  the 
barium  may  be  detected  in  it  by  the  blowpipe  test  (276). 

Artificial  sulphate  of  baryta  is  an  earthy  white  powder. 

Sulphate  of  Strontia,  SrSO4,  or  celestine  usually  occurs  in 
bluish  opaque  masses  with  a  fibrous  structure,  but  it  is  some- 
times white  or  yellowish.  The  blowpipe  test  will  indicate  the 
strontium  (244). 

Sulphate  of  Lime  and  Sulphate  of  Lead  have  been  described 
at  (69)  and  (14)  respectively. 

134.  It  sometimes  happens  that  a  slight  brown  precipi- 
tate of  platinum  sulphide  is  produced  here,  due  to  the  corro- 
sion of  the  platinum  foil  during  the  fusion. 

135.  If  tin  be  present  in  the  insoluble  substance,  it  will 
probably  also  be  detected  in  the  residue  left  on  treating  the 
fused  mass  with  water. 

The  only  compound  of  tin  likely  to  be  found  here  is  the 
Binoxide  of  Tin,  SnO2  (tinstone,  stannic  acid,  putty -powder}, 
which  occurs  naturally  either  in  separate  crystals  (stream-tin 
ore)  or  in  large  masses  (mine-tin  ore)  of  inferior  purity.  It 
is  usually  dark-colored,  heavy,  and  very  hard,  scratching 
glass  like  quartz. 

The  presence  of  tin  is  easily  confirmed  by  the  blowpipe 
(241). 

Artificial  binoxide  of  tin  is  a  white  powder  which  becomes 
yellowish  when  heated. 

Putty-poAvder  commonly  contains  oxide  of  lead  as  well  as 
binoxide  of  tin. 


126  SILICON. 

136.  If  antimony  is  present  in  the  insoluble  substance, 
the  greater  part  of  it  will  probably  be  found,  as  antimoniate 
of  soda,  in  that  portion  of  the  fused  mass  which  is  insoluble 
in  water. 

Antimonic  Acid,  Sb205,  the  only  insoluble  compound  of 
antimony  likely  to  be  met  with  here,  is  a  white  powder  which 
assumes  a  yellow  tint  when  heated. 

137.  For  confirmatory  evidence  of  the  presence  of  silicic 
acid,  see  (118,  119). 

Silicon  or  silicium  itself,  Si,  would  have  been  converted 
into  silicic  acid  by  the  fusion  with  carbonate  of  soda.  Its 
commonest  form  is  that  of  a  dark  powder  which  dissolves 
when  boiled  with  potash.  If  a  little  silicon  be  placed  on  a 
piece  of  platinum  foil  and  sharply  heated  by  directing  a  blow- 
pipe-flame upon  the  under  surface  of  the  foil,  it  eats  a 
hole  in  the  metal,  converting  it  into  the  fusible  silicide  of 
platinum. 

The  so-called  oxide  of  silicon  which  occurs  in  the  residue 
left  when  cast  iron  is  dissolved  in  hydrochloric  acid,  is  a 
gray,  very  light  powder,  which  is  easily  dissolved  with 
effervescence  when  heated  with  solution  of  potash,  hydrogen 
being  evolved,  which  is  recognized  by  its  inflammability. 

Silicic  Acid  or  silica,  SiO2,  is  met  with  in  a  variety  of 
forms,  of  which  the  following  are  the  most  important. 

Sand  is  of  various  shades  of  color.  It  is  generally  found 
to  contain  a  small  quantity  of  alumina  (in  the  form  of  clay) 
and  a  little  iron. 

Flint  is  known  by  its  characteristic  appearance. 

Quartz  occurs  in  rounded  pebbles  or  in  transparent  masses, 
sometimes  of  a  pink  color.  It  is  also  commonly  met  with 
in  well-defined  six-sided  prisms  with  pyramidal  terminations. 
Both  quartz  and  flint  scratch  glass  easily. 

Chalcedony  varies  very  much  in  color,  its  commonest  form 
is  milk-white  and  opaque. 

Soluble  Silica  is  found  in  dull  white  earthy  masses,  or,  in 
volcanic  districts,  in  porous  lumps  like  pumice,  often  stained 


CLAY.  127 

yellow  with  perchloride  of  iron.     It  is  easily  dissolved  when 
boiled  with  solution  of  potash. 

COMMON  SIMPLE  SILICATES. 

Names.  Composition. 

Clay  Silicic  acid,  alumina,  water. 

Pumice  Silicic  acid,  alumina. 

Slate  Silicic  acid,  alumina. 

Steatite  Silicic  acid,  magnesia. 

Meerschaum  Silicic  acid,  magnesia. 

Iron  slags  Silicic  acid,  oxide  of  iron. 

Electric  calamine  Silicic  acid,  oxide  or  zinc,  water. 

Clay*  (silicate  of  alumina)  occurs  in  various  degrees  of 
purity,  and  may  be  generally  recognized  by  its  plasticity 
when  mixed  with  water. 

By  heating  clay  for  some  time  with  strong  sulphuric  acid, 
a  part  of  it  is  decomposed,  and  if,  after  cooling,  the  mixture 
be  diluted  with  water  and  filtered,  it  gives,  when  mixed  with 
excess  of  ammonia,  the  characteristic  gelatinous  precipitate 
of  alumina. 

Pipe-clay  and  Kaolin  are  white,  and  consist  of  nearly  pure 
silicate  of  alumina. 

Fire  clay  (Stourbridge  clay)  has  a  gray  color,  and  con- 
tains a  little  iron.  Fire-brick  (baked  fire-clay)  has  a  yel- 
lowish hue,  from  the  presence  of  ferric  oxide. 

Dinas  fire-brick  consists  almost  entirely  of  silica. 

Common  Clay  has  various  shades  of  blue,  yellow,  and  red, 
and  often  contains  considerable  quantities  of  iron  and  lime. 

Fuller's  Earth  is  a  brown  clay  containing  iron. 

Brick,  earthenware,  and  porcelain,  since  they  are  com- 
posed chiefly  of  baked  clay,  contain  silicate  of  alumina,  the 
two  former  sometimes  containing  much  iron. 

When  clay  is  fused,  as  directed  in  the  table,  the  greater 

*  Kaolinite,  which  appears  to  form  the  basis  of  the  varieties  of 
clay,  has  the  composition  Al203.2Si0.2.2Aq. 


128  SIMPLE    SILICATES. 

part  of  the  silica  is  not  found  in  the  aqueous  solution  of  the 
fused  mass  (as  is  the  case  with  most  other  silicates),  but  in  a 
gelatinous  residue  of  silicate  of  alumina  which  is  left  undis- 
solved  by  water,  but  dissolves  in  acids. 

Pumice  and  Slate  are  known  by  their  appearance. 

Steatite,  3Mg0.4Si02,  Soap-stone,  or  French  Chalk  (sili- 
cate of  magnesia),  is  recognized  by  its  peculiar  soapy  feel 
when  rubbed  in  the  fingers. 

Meerschaum,  2MgO.3SiO2.2Aq.,  is  a  white  earthy  mine- 
ral, met  with  in  rounded  masses. 

Iron  Slag  (silicate  of  iron)  has  been  described  at  (p.  56). 

Electric  Calamine  (hydrated  silicate  of  zinc),  or  zinc 
glance,  2ZnO.SiO2Aq.,  is  usually  grayish- white,  with  a  glassy 
lustre.  When  the  mineral  is  boiled  with  hydrochloric  acid, 
the  silica  separates  in  the  gelatinous  state,  and  the  zinc  is 
dissolved  in  the  form  of  chloride. 

138.  It  is  of  course  unnecessary  to  examine  for  potas- 
sium, sodium,  and  ammonium  in  this  solution. 

139.  Any  portion  of  the  substance  which  has  not  been 
finally  powdered  is  likely  to  be  left  here. 

140.  Chrome-iron  ore  is  never  completely  attacked  by 
the  fusion,  and  may  be  recognized  by  fusing  it  on  platinum 
foil  with  carbonate  of  soda  and  nitrate  of  potash.     On  soaking 
the  foil  in  warm  water,  a  yellow  solution  is   obtained  which 
should  be  filtered,  acidified  with  acetic  acid,  and  tested  with 
lead  acetate,  which  gives  a  yellow  precipitate.     The  undis- 
solved  residue  may  be  dissolved  in  strong  hydrochloric  acid 
and  tested  for  iron  (44). 

Carbon  in  some  very  incombustible  forms,  may  also  be  left 
here.  Such  carbon  can  only  be  consumed  by  protracted 
heating  in  a  muffle. 

141.  Examples  for  Practice  in  Table  I. — The  following 
substances  may  be  analyzed  for  practice.     See  (10). 


Fluor  spar 
Plaster  of  Paris 
Binoxide  of  tin 


Sulphate  of  baryta 
Sulphate  of  lead 
White  sand. 


TABLE    K. 


129 


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130 


TABLE    L. 


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TABLES    M    AND    N. 


131 


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bl  Uric 


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132  ORGANIC    ACIDS. 

NOTES  TO  TABLES  K,  L,  M,  AND  N, 

146.  Much  attention  should  be  paid  to  the  odor  evolved 
on  heating  the  substance,  since  many  organic  acids  may  be 
at  once  recognized  in  this  way.     The  analyst  is  recommended 
to  render  himself  familiar  with  the  characteristic  odors  by 
heating  small  specimens  of  each  of  the  organic  acids. 

Tartaric  Acid  evolves  a  sweetish  odor,  somewhat  like  that 
of  burnt  sugar. 

Citric  Acid  evolves  a  similar  odor,  but  more  pungent. 

The  compounds  of  Acetic  Acid  give  the  peculiar  fragrant 
odor  of  acetone. 

Benzole  Acid  gives  the  aroma  of  frankincense. 

Succinic  Acid  emits  vapors  which  provoke  coughing. 

Hippuric  Acid  furnishes  an  odor  resembling  bitter 
almonds. 

Uric  Acid  evolves  a  smell  of  singed  hair,  in  which  a  keen 
scent  will  trace  ammonia  and  hydrocyanic  acid. 

147.  If  the  substance  leaves  no  residue  when  heated,  it 
is  not   likely  to  contain  any  metal   except   ammonium  or 
mercury. 

Ammonium  may  at  once  be  sought  by  boiling  the  sub- 
stance with  solution  of  potash,  which  would  evolve  the  pun- 
gent odor  of  ammonia.* 

Mercury  would  be  detected  by  boiling  the  substance  with 
dilute  hydrochloric  acid  and  slips  of  metallic  copper,  which 
would  become  coated  with  a  silvery  deposit,  yielding  globules 
of  mercury  when  dried  and  heated  in  a  small  tube. 

Proceed  to  detect  the  acid,  as  in  column  2,  Table  K. 

148.  The  red  color  caused  by  acetic  acid  (due  to  the 
formation  of  peracetate  of  iron  or  ferric  acetate)  should  not 

*  It  must  be  remembered  that  urea  also  evolves  ammonia  when 
boiled  with  potash ;  but  urea,  unlike  ammonia,  is  not  precipitated 


ACETIC    ACID.       ACETATES.  133 

be  bleached  by  chloride  of  mercury  (in  which  it  differs  from 
that  caused  by  the  hydrosulphocyanic  acid). 

To  obtain  confirmatory  evidence  of  the  presence  of  acetic 
acid,  heat  the  substance  with  alcohol  and  concentrated  sul- 
phuric acid,  which  should  evolve  the  pleasant  smell  of  acetic 
ether,  resembling  that  of  cider. 

149.  Acetic  Acid,  HC2H3O2,  itself  is  a  colorless  liquid, 
having  the  acid  smell  of  vinegar,  without  its  aroma.  It 
evaporates  when  heated  on  a  slip  of  glass,  without  leaving 
any  residue. 

If  acetic  acid  is  carefully  neutralized  with  ammonia  or 
carbonate  of  ammonia,  and  a  little  nitrate  of  silver  added,  a 
crystalline  precipitate  of  acetate  of  silver  separates,  especially 
on  stirring  briskly  with  a  glass  rod.  The  silver  is  not 
reduced  to  the  metallic  state  on  heating  the  precipitate  with 
the  liquid  (as  would  be  the  case  with  formic  acid,  which,  in 
other  respects,  might  be  mistaken  for  acetic). 

Acetic  acid  yields  a  crystalline  precipitate  with  mercurous 
nitrate  (protonitrate  of  mercury),  if 'the  mixture  be  stirred 
briskly  with  a  glass  rod. 

Acetic  acid  is  also  characterized  by  its  property  of  acquir- 
ing an  alkaline  reaction  to  red  litmus,  when  boiled  with 
oxide  of  lead  (litharge),  in  consequence  of  the  formation  of 
the  basic  acetate  of  lead. 

The  most  commonly  occurring  salts  of  acetic  acid  are 
Acetate  of  Lead  (14),  Tribasic  Acetate  of  Lead,  Acetate  of 
Copper  (27),  Acetate  of  Alumina  (51),  Acetate  of  Iron, 
Acetate  of  Potash,  Acetate  of  Soda,  and  Acetate  of  Ammonia. 

Tribasic  Acetate  of  Lead  (or  Goulard's  extract),  Pb2C2 
H3O2.2PbO.Aq.,  is  commonly  sold  in  solution,  though  it  may 
be  crystallized  in  needles.  It  has  a  sweet  taste,  and  turns 
red  litmus  paper  blue.  On  breathing  into  a  test-tube  con- 
taining a  little  of  the  solution,  and  shaking  it  up,  a  white 


134  FORMIC    AND    MECONIC    ACIDS. 

precipitate  of  carbonate  of  lead  is  produced.  Addition  of 
common  water  to  the  solution  also  renders  it  milky. 

Acetate  of  Iron  (ferric  acetate),  Fe3C2H3O2,  forms  a  deep 
red  solution,  which  is  changed  to  yellow  by  hydrochloric 
acid.  When  a  solution  of  ferric  acetate  is  mixed  with  three 
or  four  times  its  volume  of  water  and  boiled,  a  brown  pre- 
cipitate of  basic  ferric  acetate  is  deposited. 

Acetate  of  Potash,  KC2II3O2,  is  commonly  sold  in  white 
opaque  fibrous  masses,  having  a  faint  acetic  odor,  and  easily 
absorbing  moisture  from  the  air.  It  is  very  soluble  in  water, 
and  the  solution  gives  a  bright  red  color  with  perchloride  of 
iron. 

When  heated  on  platinum  foil,  acetate  of  potash  fuses 
easily,  evolves  inflammable  vapors,  and  leaves  a  residue  of 
carbonate  of  potash,  which  is  strongly  alkaline  to  moistened 
red  litmus  paper,  and  effervesces  with  hydrochloric  acid. 

Acetate  of  Soda,  NaC2H302.3Aq.,  is  sold  either  in  moist 
transparent  crystals  or  in  grayish  fibrous  masses  which  have 
been  fused.  In  other  respects  it  resembles  acetate  of  potash, 
but  the  residue  of  carbonate  of  soda,  which  it  leaves  when 
burnt  on  platinum  foil,  does  not  deliquesce  in  air  like  the 
carbonate  of  potash.  It  is  very  fusible,  and  requires  a  high 
temperature  to  decompose  it. 

Acetate  of  Ammonia,  NH4C2H3O2,  is  generally  met  with 
in  solution  ;  on  boiling  it,  the  odors  of  acetic  acid  and  am- 
monia may  be  perceived. 

150.  Formic  Acid,  IICHO2,  is  a  colorless  liquid  of  pun- 
gent odor,  resembling  that  of  acetic  acid.  It  leaves  no 
residue  when  evaporated.  When  formic  acid  is  heated  with 
nitrate  of  silver  or  bichloride  of  platinum,  black  deposits  of 
the  metals  are  obtained,  especially  if  a  little  ammonia  is 
added. 

The  formiates  of  potassium  and  sodium,  when  heated  with 
strong  sulphuric  acid,  evolve  carbonic  oxide  abundantly, 
which  burns  with  a  blue  flame  on  applying  the  mouth  of  the 
tube  to  a  light. 


TANNIC    AND    GALLIC    ACIDS.  135 

151.  Meconic  Acid,  H3C7HO..3Aq.,  forms  scaly  crystals 
which  have  commonly  a  brownish  color,  and  dissolve  with 
difficulty  in  cold,  but  easily  in  hot  water.     Alcohol  also  dis- 
solves them. 

The  red  color  produced  by  perchloride  of  iron  with  nie- 
conic  acid  is  not  bleached  by  chloride  of  mercury  (thus 
distinguishing  it  from  hydrosulphocyanic  acid). 

A  solution  of  meconic  acid  which  has  been  mixed  with 
excess  of  ammonia,  gives  a  white  precipitate  with  chloride  of 
calcium,  which  is  soluble  in  acetic  acid. 

None  of  the  meconates  are  of  common  occurrence.  Meco- 
nate  of  morphia  is  sometimes  used  in  medicine. 

152.  Tannic  Acid  (or  tannin),  CJ4H10O9,  is  a  yellowish 
or  brownish  powder,  which  has  a  very  astringent  taste,  and 
dissolves  pretty  easily  when  shaken  with  cold  water. 

On  adding  potash  or  ammonia  to  a  solution  of  tannic  acid, 
it  becomes  brown,  especially  if  shaken  with  air. 

Dilute  sulphuric  acid,  added  in  considerable  quantity, 
causes  a  white  precipitate  in  solution  of  tannic  acid.  When 
the  solution  has  been  kept  for  some  time,  it  fails  to  give  this 
precipitate. 

The  only  tannate  commonly  met  with  is  that  of  sesqui- 
oxide  of  iron  (ferric  tannate)  which  exists  in  writing  ink. 

Ink  may  be  identified  by  adding  strong  nitric  acid,  which 
reddens  it,  and  changes  it  to  a  clear  yellow  on  boiling.  On 
adding  excess  of  ammonia,  the.  rusty  brown  sesquioxide  of 
iron  is  precipitated. 

153.  Gallic  Acid,   HC7H5O.,   is    a  white    or  yellowish 
powder  composed    of   minute    shining  needles.       It  is    not 
visibly  dissolved  when  shaken  with  cold  water,  but  dissolves 
readily  on  boiling,  being  deposited  again  in  delicate  needles 
when  the  solution  cools. 

Potash  or  ammonia  causes  a  red-brown  color  in  a  solu- 
tion of  gallic  acid,  which  becomes  much  darker  on  shaking 
with  air. 


136  SUCCINIC    AND    HIPPURIC    ACIDS. 

There  is  no  gallate  of  common  occurrence. 

154.  Be  quite  sure  that  this  brown  precipitate  is  not  the 
peroxide  of  iron  precipitated  because  the  original  solution 
was  alkaline. 

Benzoic  Acid,  HC7H5Oa,  is  commonly  met  with  in  white 
feathery  crystals,  which  are  extremely  light  and  have  an 
agreeable  odor  of  incense.  It  has  a  peculiar  sweetish  pun- 
gent taste,  and  is  not  easily  dissolved  by  water.  It  dissolves 
easily  in  ammonia,  and  is  reprecipitated  in  feathery  flakes  on 
adding  excess  of  hydrochloric  acid,  if  the  solution  be  not  too 
dilute. 

When  gently  heated  in  a  tube,  it  fuses  easily,  and  sub- 
limes without  leaving  any  residue  of  importance.  Hippuric 
acid  (156)  much  resembles  benzoic. 

None  of  the  benzoates  are  sufficiently  common  to  require 
special  description. 

155.  The  precipitate   is  of  a  much  darker  red-brown 
color  in  the  case  of  succinic  than  in  that  of  benzoic  acid. 

Succinic  Acid,  H2C4H4O4,  is  a  colorless  crystalline  acid, 
which  dissolves  easily  even  in  cold  water.  The  solution 
when  mixed  with  excess  of  ammonia  and  chloride  of  barium, 
does  not  give  any  precipitate ;  but  if  alcohol  be  added,  the 
liquid  deposits  succinate  of  baryta  as  a  white  precipitate. 

Succinic  acid  is  characterized  by  its  behavior  when 
heated;  it  first  melts,  and  is  then  decomposed,  evolving 
vapors  which  produce  violent  coughing.  It  leaves  a  very 
slight  carbonaceous  residue,  which  easily  burns  away. 

No  salt  of  succinic  acid  can  be  described  as  being  com- 
monly met  with. 

156.  Hippuric  Acid,  HC9H8NO3,  forms   shining   pris- 
matic crystals  which  are  nearly  insoluble  in  cold  water,  but 
dissolve  readily  on  boiling,  and  are  deposited  as  the  liquid 
cools.     It  is  almost  insoluble  in  ether,  and  may  thus  be  dis- 
tinguished from  benzoic  acid,  which  dissolves  easily  in  ether. 

When  heated  in  a  tube,  hippuric  acid  melts  and  is  decom- 
nosed.  evolving  an  asrreeable  odor  (of  benzonitrile,  CJLN) 


TARTARIC    ACID.  137 

resembling  oil  of  bitter  almonds,  and  leaving  a  carbonaceous 
residue. 

When  heated  with  strong  sulphuric  acid,  hippuric  acid 
blackens  more  easily,  and  evolves  more  sulphurous  acid  than 
benzoic  acid  does.  If  hippuric  acid  be  dissolved  in  potash 
and  evaporate  to  dryness,  the  residue  evolves  ammonia 
when  heated.  Benzoic  acid,  being  free  from  nitrogen,  could 
not  furnish  ammonia  when  thus  treated. 

The  hippurates  are  not  commonly  met  with. 

157.  The  behavior  of  the  precipitate  of  tartrate  of  lime 
is  very  characteristic,  and  should  be  carefully  observed. 

When  precipitated,  as  in  Table  L,  from  an  ammoniacal 
solution,  it  is  flocculent  or  gelatinous,  according  to  the 
strength  of  the  solution  ;  but  if  it  be  set  aside  for  some  time, 
it  becomes  a  granular  crystalline  precipitate. 

The  flocculent  tartrate  of  lime  dissolves  easily  in  chloride 
of  ammonium,  and  is  deposited  again  in  a  crystalline  state  if 
the  sides  of  the  tube  beneath  the  liquid  be  well  rubbed  with 
a  glass  rod.* 

Crystalline  tartrate  of  lime  does  not  dissolve  when  shaken 
with  chloride  of  ammonium,  and  not  easily  in  acetic  acid, 
so  that  it  might  at  first  be  mistaken  for  oxalate  of  lime;  but 
if  it  be  dissolved  in  hydrochloric  acid,  and  an  excess  of 
ammonia  added,  it  is  not  immediately  reprecipitated,  as 
would  be  the  case  with  oxalate  of  lime,  but  requires  brisk 
stirring  with  a  glass  rod,  when  it  again  separates  in  a  crystal- 
line state. 

158.  Tartaric  Acid,  U^CJIfl^  itself  is  sold  either  in 
colorless  crystals,  or  as  a  white  powder.    It  dissolves  readily, 
even  in  cold  water,  giving  a  strongly  acid  solution. 

When  heated,  tartaric  acid  melts,  carbonizes,  and  evolves 
a  peculiar  odor,  somewhat  resembling  that  of  burnt  sugar ; 

*  The  tartrate  of  lime  precipitated  from  tartar  emetic  does  not 
exhibit  this  disposition  to  become  crystalline. 


138  TARTAKIC    ACID. 

the  remaining  carbon  burns  off  without  any  residue  if  the 
acid  is  pure. 

When  heated  with  strong  sulphuric  acid  tartaric  acid 
soon  gives  a  very  black  solution,  and  evolves  a  little  carbonic 
oxide,  which  burns  with  a  blue  flame  on  applying  the  mouth 
of  the  tube  to  a  light. 

Lime-water,  added  in  excess  to  a  very  small  quantity  of 
solution  of  tartaric  acid,  gives  a  white  precipitate  of  tartrate 
of  lime,  soluble  in  chloride  of  ammonium. 

A  solution  of  tartaric  acid,  mixed  with  a  small  quantity  of 
chloride  of  calcium,  gives  no  precipitate;  but  if  potash  be 
gradually  added,  tartrate  of  lime  is  precipitated,  which  dis- 
solves in  an  excess  of  potash,  and  is  reprecipifated  on  boiling 
the  solution,  dissolving  again  as  it  cools. 

If  much  chloride  of  calcium  be  employed,  some  carbonate 
of  lime  is  precipitated  by  the  carbonic  acid  in  the  potash,  and 
this  does  not  dissolve  in  the  excess  of  potash. 

Acetate  of  lead,  added  to  a  solution  of  tartaric  acid,  pro- 
duces a  white  precipitate  of  tartrate  of  lead,  which  is  easily 
soluble  in  ammonia. 

If  a  solution  containing  tartaric  acid  be  mixed  with  potash 
in  excess  and  permanganate  of  potash,  the  green  color  at 
first  produced  will  disappear  on  boiling,  a  brown  precipitate 
of  manganic  oxide  being  separated  (see  citric  acid). 

The  salts  of  tartaric  acid  commonly  met  with,  are  Bitar- 
trate  of  Potash,  Tartrate  of  Antimony  and  Potash,  .and 
Tartrate  of  Potash  and  Soda. 

Bitartrate  of  Potash  has  been  described  at  (p.  83). 

By  dissolving  it  in  a  very  small  quantity  of  potash,  and 
adding  a  little  chloride  of  calcium,  the  white  precipitate  of 
tartrate  of  lime  may  be  obtained,  which  dissolves  in  an 
excess  of  potash,  and  is  reprecipitated  by  boiling. 


CITRIC    ACID.  139 

Tartrate  of  Antimony  and  Potash  has  been  noticed  at  (39). 

Its  solution  in  water  is  slightly  acid,  and  gives,  after  a 
short  time,  a  white  precipitate  of  teroxide  of  antimony  on 
adding  ammonia;  this  may  be  filtered  off,  and  the  solution 
tested  with  chloride  of  calcium  (Io7). 

Tartrate  of  Potash  and  Soda,  or  Rochelle  salt,  KNaC4H4 
O6.4Aq.,  forms  large  transparent  prismatic  crystals,  which 
dissolve  easily  in  water.  If  the  solution  be  slightly  acidified 
Avith  acetic  acid,  and  briskly  stirred,  a  crystalline  precipitate 
of  bitartrate  of  potash  is  deposited. 

159.  The  precipitation  by  chloride  of  calcium  in  an 
ammoniacal  solution  on  boiling,  must  not  be  regarded  as 
satisfactory  proof  of  the  presence  of  citric  acid,  since  other 
precipitates,  particularly  carbonate  and  sulphate  of  lime, 
may,  under  some  conditions,  be  obtained  in  a  similar  way. 

Citric  Acid,  H3C6H507. Aq.,  forms  colorless  crystals,  which 
are  readily  dissolved  by  cold  water. 

When  heated,  the  crystals  fuse,  carbonize,  and  emit  irri- 
tating inflammable  vapors,  very  different  from  those  evolved 
by  tartaric  acid.  Citric  acid  also  leaves  less  charcoal  than 
tartaric.  The  charcoal  burns  away  entirely  if  the  acid  is 
pure. 

Strong  sulphuric  acid  heated  Avith  citric  acid,  evolves 
much  carbonic  oxide  gas,  recognized  by  its  burning  with  a 
blue  color  on  applying  the  mouth  of  the  tube  to  a  flame; 
the  mixture  does  not  carbonize  so  readily  as  in  the  case  of 
tartaric  acid. 

Lime-water,  added  in  large  excess  to  a  very  small  quantity 
of  solution  of  citric  acid,  does  not  produce  a  precipitate  until 
the  mixture  is  boiled,  when  citrate  of  lime  is  deposited.  On 
cooling  the  solution,  the  precipitate  will,  at  least  partly,  be 
redissolved,  since  citrate  of  lime  is  more  soluble  in  cold  than 
in  hot  water. 


140  CITRATES. 

gives  no  precipitate ;  but  if  potash  be  added,  citrate  of  lime 
is  separated,  which  does  not  redissolve,  like  tartrate  of  lime, 
on  adding  an  excess  of  potash. 

If  a  solution  containing  citric  acid  be  mixed  with  potash 
in  excess  and  permanganate  of  potash,  the  latter  will  be 
changed  to  the  green  manganate  of  potash,  which  will  not 
become  brown  on  boiling  (see  tartaric  acid). 

The  only  citrates  which  are  at  all  commonly  met  with 
are  the  medicinal  preparations — citrate  of  iron,  ammonio- 
citrate  of  iron,  citrate  of  iron  and  quinine,  and  citrate  of 
bismuth. 

Citrates  of  lime  and  magnesia  are  imported  from  Sicily, 
for  the  preparation  of  citric  acid. 

Citrate  of  Iron  (ferric  citrate)  forms  brilliant  red  or  yellow 
transparent  scales,  which  taste  sweet  and  astringent ;  they 
dissolve  readily  in  water,  forming  a  brown  solution  which 
is  precipitated  by  alcohol.  The  presence  of  citric  aeid 
prevents  the  precipitation  of  the  ferric  oxide  on  addition  of 
ammonia. 

Ammonio- citrate  of  Iron  is  very  similar  to  the  citrate. 

Citrate  of  Iron  and  Quinine  also  forms  fine  yellow  scales, 
in  which,  however,  the  bitter  taste  of  quinine  is  perceptible. 
Its  solution  yields  a  white  precipitate  of  quinine  on  addition 
of  ammonia.* 

Citrate  of  Bismuth  is  remarkable  as  being  the  only  prepa- 
ration of  bismuth  which  can  be  dissolved  in  water  without 
decomposition. 

By  decomposing  its  solution  with  hydrosulphuric  acid,  the 
bismuth  may  be  precipitated  as  sulphide,  and  the  filtered 
solution,  after  evaporating  to  expel  excess  of  hydrosulphuric 
acid,  may  be  tested  for  citric  acid. 

*  The  citrate  of  iron  and  quinine  of  the  Pharmacopoeia  contains 
both  ferrous  and  ferric  oxides,  so  that  it  yields  a  dark  blue  color 
with  both  ferrocyanide  and  ferricyanide  of  potassium. 


MALIC    ACID.       URIC    ACID.  141 

In  the  medicinal  preparation,  citrate  of  ammonia  is  usually 
present. 

Citrate  of  Lime,  Ca32C6H5O?.4Aq.,  is  a  white  powder 
which  turns  red  litmus  blue.  It  dissolves  sparingly  in  water, 
but  readily  in  hydrochloric  acid.  Ammonia  precipitates  the 
solution  only  when  boiled.  When  heated  on  platinum,  it  is 
charred  and  decomposed,  leaving  a  residue  of  carbonate  of 
lime,  which  effervesces  with  hydrochloric  acid. 

Citrate  of  Magnesia,  Mg32C6H.O7.14Aq.,  is  a  crystalline 
granular  salt,  which  is  more  soluble  in  water  than  the  citrate 
of  lime. 

The  so-called  "granulated  effervescing  citrate  of  magne- 
sia" is  often  composed  of  a  mixture  of  carbonate  of  soda  with 
citric,  or  occasionally  tartaric,  acid,  which  do  not  act  upon 
each  other  until  water  is  added. 

159«.  The  chance  of  error  from  this  cause  is  diminished 
by  mixing  the  original  solution  with  carbonate  of  ammonia 
until  it  is  slightly  alkaline,  and  evaporating  at  a  gentle  heat 
till  it  is  neutral. 

160.  This  is  a  very  satisfactory  test  for  mallic  acid,  if  the 
solution  be  not  too  dilute  and  a  large  excess  of  lead  acetate 
be  avoided.     The  malate  of  lead  fuses  into  a  white  opaque 
drop,  which  feels  sticky  when  touched  with  a  glass  rod. 

The  crystallized  mallic  acid  is  somewhat  deliquescent,  has 
an  agreeable  sour  taste,  and  dissolves  easily  in  water  and 
alcohol.  When  heated  in  a  tube  it  fuses  easily,  and  is  after- 
wards decomposed,  with  effervescence,  evolving  very  pun- 
gent vapors  of  fumaric  and  malaeic  acids,  which  condense  in 
crystals  upon  the  cool  part  of  the  tube.* 

161.  The  presence  of  uric  acid  may  be  confirmed  by  the 
test  given  in  column  2  of  Table  N. 

Uric  Acid  (or  lithic  acid],  H2C5H2N4O3,  itself  is  a  white 
or  yellowish  white  crystalline  powder,  which  dissolves  very 

*  The  malic  acid  of  commerce  sometimes  contains  a  little  oxalic 
acid  as  an  impurity. 


142  URATES    OR    LITIIATES. 

sparingly,  even  in  boiling  water.  It  is  also  nearly  insoluble 
in  hydrochloric  acid,  but  dissolves  on  boiling  in  dilute  nitric 
acid,  with  brisk  effervescence.  It  is  also  dissolved  when 
heated  with  a  moderately  strong  solution  of  potash,  and  is 
reprecipitated  from  this  solution  in  a  crystalline  state,  on 
adding  a  slight  excess  of  hydrochloric  acid. 

When  heated,  uric  acid  is  carbonized,  and  emits  vapors  in 
which  the  smell  of  ammonia  and  that  of  hydrocyanic  acid 
can  be  distinguished. 

On  platinum  foil,  uric  acid,  if  pure,  burns  without  residue. 

Strong  sulphuric  acid  does  not  blacken  uric  acid  to  any 
great  extent,  even  on  heating,  but  dissolves  it,  in  great 
measure  without  change.  On  allowing  the  solution  to  cool, 
and  adding  water,  the  greater  part  of  the  uric  acid  is  pre- 
cipitated. 

The  uric  acid  deposited  from  urine  and  occurring  in  uri- 
nary calculi,  is  often  colored  yellow  or  brown  by  coloring 
matters  derived  from  the  urine. 

The  urates  of  soda  and  ammonia  are  commonly  met  with 
as  deposits  from  urine,  colored  yellow,  brown,  or  red,. by  the 
coloring  matters  of  that  excretion.  They  are  both  dissolved 
when  heated  with  water,  and  deposited  again  as  the  solution 
cools.  On  adding  hydrochloric  acid  to  the  warm  solution, 
crystalline  uric  acid  is  precipitated. 

Urate  of  Ammonia,  NH4HC5H2N403,  of  course,  evolves 
the  smell  of  ammonia  when  boiled  with  potash. 

Urate  of  Soda,  NaHC3H2N4O3,  when  heated  on  platinum 
foil,  leaves  a  residue  of  carbonate  of  soda,  recognized  by  its 
solubility  in  water,  giving  a  strongly  alkaline  solution,  which 
effervesces  with  hydrochloric  acid. 

161«.  In  some  cases  it  is  difficult  to  identify  the 
organic  acid  in  n,  salt,  until  the  mo.tnl  hns  been  removed. 


EXAMPLES    FOR    PRACTICE.  143 

Where  the  present  metal  belongs  to  either  of  the  first  three 
classes  (p.  18),  the  salt  may  be  suspended  or  dissolved  in 
water,  treated  with  an  excess  of  hydrosulphuric  acid,  filtered 
from  the  metallic  sulphide,  evaporated  to  a  small  bulk,  and 
tested  by  Table  L.  Salts  of  barium,  strontium,  calcium, 
and  magnesium  may  be  boiled  with  carbonate  of  soda,  fil- 
tered, and  the  solution  examined  by  Table  M. 

Some  of  the  rarer  organic  acids  are  described  at  (174, 
215,  218,  232). 

162.    Examples  for  Practice  in   Tables  K,  L,  M,  and 

N The  following  substances  may  be  analyzed  for  practice 

(10):- 


Tartaric  acid 
Bitartrate  of  potash 
Tartar  emetic 
Acetate  of  lead 
Uric  acid 


Tannic  acid 
Gallic  acid 
Benzoic  acid 
Citric  acid 
Acetate  of  soda. 


144 


TABLE    O. 


s 

"8 

bo 

0 


ho 


I 

0 

i! 


d  a 


•+J 

•8 


CO 

CO 


p 

cr 

"§ 

^s 


8  5  2  •!  >  1 1  "8 


5   a 

S  'i 


a  « 

co    <=  '  - 


"S  la       fc   ® 

i  I    s w 


^s  § 


m 
ol 


HO 

.2    s    w 


;  2 


S     ^s 

3-E    1 


ed. 


ssolv 
See 
umn 


ve 
in 


MORPHINE    OK    MORPHIA.  145 

NOTES  TO  TABLE  O. 

164.  Caffeine  would  give  no  precipitate  with  potash,  and 
would  have  escaped  detection  in  the  Table. 

Caffeine  (or  Theine),  C8H10N4O2.Aq.,  crystallizes  in  nee- 
dles, which  have  a  somewhat  bitter  taste,  and  dissolves 
slightly  in  cold  water,  but  entirely  in  boiling  water  ;  the  solu- 
tion is  neutral.  It  is  also  soluble  in  alcohol  and  ether. 
Gently  heated  in  a  tube,  caffeine  fuses  and  sublimes  in  fine 
needles.  To  identify  it,  dissolve  it  in  very  little  strong  hy- 
drochloric acid,  add  a  small  crystal  of  chlorate  of  potash,  and 
evaporate  just  to  dryness  :  the  residue  has  a  pink  or  red  color, 
and  dissolves  in  ammonia  to  a  fine  purple  liquid,  which  is 
bleached  by  potash. 

165.  Morphine    C17H19NO3.Aq.,   is  a  white    crystalline 
powder,   which  dissolves   sparingly  even    in  boiling  water, 
yielding  a  bitter  solution,  which  is  alkaline  to  test-papers.     It 
is  also  soluble  in  alcohol,  but  not  in  ether. 

Strong  nitric  acid  colors  morphine  orange-yellow,  and 
produces  a  similar  color  in  solutions  containing  morphine. 

Perchloride  of  iron  (ferric  chloride),  free  from  excess  of 
acid,  colors  morphine  inky  blue. 

Morphine,  heated  with  strong  sulphuric  acid,  and  stirred 
with  a  glass  rod  moistened  with  nitric  acid,  gives  a  rapid 
play  of  colors,  from  dingy  green  to  a  rich  brown. 

The  hydrochlorate  (muriate),  meconate,  and  acetate  of 
morphine  are  easily  soluble  in  water.  By  mixing  the  aqueous 
solution  with  carbonate  of  soda,  and  stirring  briskly,  the 
morphine  is  precipitated,  and  may  be  collected  upon  a  filter, 
washed  with  cold  water,  and  tested  with  perchloride  of  iron 
or  with  nitric  acid. 

Meconate  of  Morphine  is  not  crystallizable. 


146  STRYCHNINE.       QUININE. 

Acetate  of  Morphine,  C]7H1DNO3.C2H4O2,  is  crystalline, 
but  very  deliquescent. 

Hydrochlorate  of  Morphine  is  crystalline,  CnH1BNOa. 
HCl.SAq.,  and  not  deliquescent. 

The  acids  may  be  detected  as  in  Tables  H  and  L. 

166.  Brucine,  C23H26N2O4.4Aq.,  is    a  white    crystalline 
powder,  which  may  be  dissolved  by  boiling  water,  yielding 
a  bitter  solution.     It  also  dissolves  in  alcohol,  but  not  in 
ether. 

Strong  nitric  acid  gives  a  bright  red  solution  with  brucine 
which  becomes  yellow  when  heated.  Protochloride  of  tin 
(stannous  chloride)  changes  the  yellow  color  to  violet. 

If  brucine  be  dissolved  in  a  drop  or  two  of  diluted  hydro- 
chloric acid,  and  ammonia  carefully  added,  an  oily-looking 
precipitate  of  brucine  separates,  which  afterwards  changes  to 
needle-like  crystals.  Excess  of  ammonia  dissolves  the  oily 
precipitate,  and  the  solution  deposits  the  needles  after  some 
time. 

167.  Strychnine,  C21H22N2O2,  is  met  with  either  as  a  fine 
white  powder,  or  in  hard  prismatic  crystals.     It  is  scarcely 
perceptibly  dissolved,  even  by  boiling  water,  but  the  solution 
has  an  intensely  bitter  taste.     It  dissolves  rather  sparingly 
in  ordinary  alcohol,  and  is  soluble  in  absolute  alcohol  and  in 
ether. 

If  strychnine  be  dissolved,  on  a  white  surface  of  porcelain, 
in  strong  sulphuric  acid,  and  stirred  with  a  few  particles  of 
binoxide  of  lead  (brown  oxide), it  gives  a  dark  violet  purple 
color,  quickly  changing  to  red.  The  test  with  bichromate 
of  potash,  given  in  Table  O,  is  far  more  delicate,  especially 
if  a  very  minute  quantity  of  the  bichromate  be  employed. 

168.  A  solution  of  bromine  in  water  may  be  substituted 
for  chlorine  water  in  testing  for  quinine.     Strong  solutions 
of  quinine  yield  a  green  precipitate  when  tested  with  chlorine 
(or   bromine)    and   ammonia.     Another    excellent   test  for 
quinine  consists  in  adding  to  the  acid  solution  a  little  chlorine 
or  bromine  water,  a  drop  or  two  of  ferridcyanide  of  potassium, 


QUININE.       NARCOTINE.  147 

and,  drop  by  drop,  ammonia,  which  produces  a  fine  red  color 
bleached  by  excess  of  ammonia. 

Quinine,  C^H^NjjO.^.SAq.,  is  a  white  crystalline  powder, 
which  is  sparingly  dissolved  even  by  hot  water,  but  dissolves 
easily  in  alcohol.  Ether  does  not  dissolve  it  so  easily.  Its 
solution  is  very  bitter,  and  is  alkaline  to  test-papers. 

If  quinine  be  dissolved  in  diluted  sulphuric  acid,  and  the 
solution  mixed  with  water  and  examined  by  daylight  in  a 
test-tube,  it  will  be  found  to  exhibit  a  very  pretty  shade  of 
blue  when  in  certain  positions,  though  it  appears  quite  color- 
less when  held  directly  between  the  eye  and  the  light. 

This  fluorescence  is  very  characteristic,  and  may  be  seen 
even  in  dilute  solutions. 

Sulphate  (or  basic  sulphate)  of  quinine,  2C20H24N2O2. 
HaS04.7Aq.,  forms  very  light  silky  needles,  which  are  very 
bitter,  and  will  not  dissolve,  even  in  boiling  water,  unless  a 
little  sulphuric  or  hydrochloric  acid  is  added. 

If  sulphate  of  quinine  is  adulterated  with  salicine,  C13H|8O7, 
it  assumes  a  red  color  when  moistened  with  strong  sulphuric 
acid. 

To  detect  the  presence  of  cinchonine,  the  sulphate  is 
shaken  in  a  test-tube  (or  small  stoppered  bottle)  with  ammo 
nia  and  ether,  when  pure  sulphate  of  quinine  entirely  dis- 
solves, the  solution  separating  into  two  layers  ;  whilst  any 
cinchonine,  being  insoluble  in  ether,  separates  on  the  surface 
of  the  lower  (aqueous)  layer. 

169.  Narcotine,  C22H23NO7,  is  a  white  crystalline  tasteless 
substance,  which  is  not  alkaline  to  moistened  test-papers.  It 
is  insoluble  in  water,  but  dissolves  in  alcohol  and  ether, 
yielding  bitter  solutions. 

To  identify  it,  dissolve  it  in  a  considerable  quantity  of 
strong  sulphuric  acid,  and  stir  the  liquid  with  a  glass  rod 
moistened  with  strong  nitric  acid,  a  dark  red  color  is  pro- 
duced, which  is  bleached  by  more  nitric  acid. 

If  a  few  drops  of  solution  of  perchloride  of  iron  be  care- 
fully added,  from  the  end  of  a  glass  rod,  to  the  solution  of 


148  CIXCHONINE. 

narcotine  in  strong  sulphuric  acid,  a  deep  red  liquid  is  pro- 
duced, which  becomes  of  a  brighter  color  on  cooling. 

If  narcotine  be  dissolved  in  dilute  hydrochloric  acid,  and  a 
little  solution  of  bromine  be  added,  a  yellow  precipitate  is 
obtained,  unless  the  solution  is  very  dilute.  On  heating, 
this  precipitate  is  dissolved,  and,  by  gradually  adding  solu- 
tion of  bromine  and  boiling,  a  fine  rose  color  is  produced, 
even  in  very  dilute  solutions.  Excess  of  bromine  destroys 
the  color. 

nO.  CVracfomVze, '  C20H24N2O,  is  white,  crystalline,  and 
slightly  bitter.  It  is  almost  insoluble  in  water,  but  dissolves 
in  alcohol,  yielding  a  bitter  solution  which  has  an  alkaline 
reaction.  Ether  does  not  dissolve  it.  Gently  heated  in  a 
tube,  cinchonine  fuses,  emits  a  peculiar  tarry  ammoniacal 
odor,  and  yields  a  sublimate  of  shining  needles  on  the  cooler 
part  of  the  tube.  Moistened  with  dilute  sulphuric  acid,  and 
heated,  it  yields  a  fine  red  coloring  matter. 

If  cinchonine  be  dissolved  in  as  little  dilute  hydrochloric 
acid  as  possible,  the  solution  gives,  with  ferrocyanide  of  po- 
tassium, a  yellow  precipitate,  which  dissolves  when  warmed 
with  a  slight  excess  of  the  ferrocyanide,  and  is  deposited  in 
yellow  scales  or  needles  on  cooling. 

/Sulphate  of  cinchonine^  2C20H24N2O.H2SO4.2Aq.,  forms 
white  or  brownish  prismatic  crystals  which  fuse  when  heated, 
and  yield  a  fine  red  coloring  matter,  as  well  as  an  aromatic 
odor. 

171.  Examples  for  Practice  in  Table  O.— The  following 
substances  may  be  examined  for  practice  (10): — 

Hydrochlorate  of  morphine         I         Sulphate  of  quinine 
Strychnine  Cinchonine. 


INDIGO.       PICRIC    ACID.  149 

EXERCISE  X.     (See  (234)  for  Examples  for  Practice.) 

172.  IDENTIFICATION  OF  THE  MORE  COMMON  ORGANIC 
SUBSTANCES.* 

1.  SOLID  ORGANIC  SUBSTANCES. 
A.    Characterized  by  color. 

173.  Indigo,  C8H5NO Dark  blue.     Insoluble  in  water, 

alcohol,  and  ether. 

Heated  in  a  tube  (17),  yields  violet  vapors,  smelling  of 
aniline  and  ammonia. 

Strong  sulphuric  acid  slowly  dissolves  indigo,  when  heated, 
giving  a  blue  solution,  which  is  changed  to  brown-yellow  by 
nitric  acid. 

Shaken  in  a  corked  tube  with  sulphate  of  iron  (ferrous 
sulphate)  and  slaked  lime,  and  allowed  to  settle,  indigo  dis- 
solves to  a  yellow  solution  (reduced  indigo,  C8H6NO),  which 
becomes  blue-green  when  decanted  and  acidulated  with 
hydrochloric  acid. 

174.  Picric  or  Carbazotic  Acid,  HC6H2O3N02 — Yellow 
crystals.     Very  bitter.      Stains  the  skin  yellow. 

Water  dissolves  it  sparingly.     Bright  yellow  solution. 

Alcohol  dissolves  it  easily.  The  solution  gives  a  yellow 
crystalline  precipitate  when  stirred  with  a  little  potash. 

Heated  in  a  tube,  fuses,  and  sometimes  explodes  slightly. 

Strong  sulphuric  acid  dissolves  it,  and  deposits  it  un- 
changed on  addition  of  water. 

Heated  with  solution  of  chloride  of  lime  (bleaching  pow- 
der), it  evolves  a  very  pungent  odor  like  oil  of  mustard,  due 
to  chloropicrine,  CC13NO2. 

175.  Caramel,  C12H1809 — Dark-brown.       Deliquescent. 
Slightly  bitter. 

Very  soluble  in  water,  dark-brown  solution. 
Sparingly  soluble  in  strong  alcohol. 

*  Excluding:  those  which  are  treated  of  in  Exercises  8  and  9. 


150  CARBOLIC  ACID  OK  FHENOLE. 

Heated  in  tube,  carbonizes,  and  emits  the  odor  of  burnt 
sugar. 

Strong  sulphuric  acid  carbonizes  it. 

B.    Characterized  by  Odor. 

176.    Carbolic  Acid  (Phenic  Acid)  ;  Phenole,  C6H6O. 

Moist  needle-like  crystals  ;  colorless  or  pale  brown.  Power- 
ful odor  of  coal-tar.  Very  easily  melted.  Water  dissolves 
it  sparingly.  Easily  soluble  in  potash. 

Alcohol  dissolves  it  readily. 

Perchloride  of  iron  (ferric  chloride)  gives  a  dark  purple- 
blue  color  with  the  aqueous  solution  of  carbolic  acid. 

Dropped  into  strong  nitric  acid,  carbolic  acid  is  oxidized 
with  great  violence,  yielding  a  red  solution  ;  if  this  be  boiled 
and  allowed  to  cool,  it  deposits  prismatic  crystals  of  picric 
acid  which  may  be  identified  by  (174). 

YlQa.  Hydrate  of  Chloral,  C2HC13O.H2O.,  white  crystal- 
line solid.  Easily  dissolved  by  water. 

Remarkable  pungent  odor. 

Easily  melted  and  volatilized. 

Heated  with  potash,  yields  an  oily-looking  layer  of  chloro- 
form and  a  solution  of  formiate  of  potash,  which  may  be 
identified  by  neutralizing  with  dilute  sulphuric  acid,  adding 
nitrate  of  silver  in  excess,  decanting  the  clear  liquid  from 
any  precipitated  chloride  of  silver,  and  boiling  it,  adding 
ammonia,  drop  by  drop,  when  metallic  silver  is  precipitated. 

C.    Without  Characteristic  Color  or  Odor. 
Examine  by  Table  P. 


TABLE    P. 


151 


be 

'•8 


1  § 

ii 


02 


.S  o 

I'i 

o  Sf 
2  O 


o  O 


'S  S 


I  SM 

S  7^    w 

I"l 

X  -^  h 

w  -H  H 


8 

03 
Q 

m 

« 
M 

1 

£ 

03 

d 

'a 

eg 
H 

o 

'o 

c/5 
CM 

rH 

E 

If  it  does  not  dissolve 

examine  by 
(206). 

3. 
Boil  the  substance 

with  ALCOHOL. 

If  it  dissolves,  examine  by 

/—  s 

CO 
0 
IH 

1 

'o 

o 
Pi 

•— 

1 

8 

a 
§ 

-     S 

03 

H 

'i 

. 

VI 

ft 

a^* 

cS 

1 
ri 
(N         w 

WATER. 

3 

x 

03 

8 

> 

fl 

o 

00 

-  dissolv< 

CO 

g 

03 

^ 

Q 

"o 

^, 

o 

Q 

^ 

c/I 

o 

^ 

'^ 

^' 

03 

I 

a 

1 

5 

0 

03 

16 

03 

-9 

substance  with 

3 

r- 
£ 

1 

for  some  time. 

'3 

j> 
'o 

.2 

ly  or  in  great  measure, 

mine  the  solution  by 

(178). 

it  does  not  dissolve, 

ass  on  to  column  2. 

<tH 

03 

ft 

02 

FH 

X 

V-i 

"3 

03 

152  CANE    AND    GRAPE    SUGARS. 


NOTES  TO  TABLE  P. 

1*78.  The  commonest  of  these  organic  substances  which 
are  dissolved  to  any  considerable  extent  by  being  shaken 
with  cold  water  are — * 


Cane-sugar 

Grape-sugar  (or  glucose) 
Milk-sugar  (or  lactine) 


Pyrogalline  (or  pyrogallic  acid) 

Salicine 

Urea 


Soluble  albumen. 

179.  Cane-sugar,  ClaH82Ou,  identified. 

Add  to  the  solution  a  few  drops  of  sulphate  of  copper,  and, 
drop  by  drop,  potash.  The  blue  precipitate  first  produced 
redissolves  in  the  excess  of  potash,  to  a  blue  liquid.  Boil 
for  some  minutes,  suboxide  of  copper  (cuprous  oxide)  is 
deposited,  first  as  a  yellow  hydrate,  afterwards  as  the  red 
anhydrous  oxide. 

To  another  part  of  the  solution,  add  excess  of  potash,  and 
boil,  only  a  very  light-brown  color  should  be  produced. 

Heat  a  portion  of  the  solid  substance  with  strong  sulphuric 
acid,  which  should  carbonize  it  almost  immediately. 

To  a  part  of  the  aqueous  solution,  add  a  few  drops  of 
dilute  hydrochloric  acid,  and  boil  for  a  few  minutes  ;  the 
cane-sugar  is  thus  converted  into  grape-sugar,  which  may  be 
identified  by  the  following  tests. 

180.  Grape-sugar,  C6H14O7,  identified. 

Add  to  the  solution  an  excess  of  potash,  and  boil.  The 
liquid  should  assume  a  rich  brown  color. 

To  another  part  of  the  solution,  add  a  few  drops  of  sulphate 
of  copper,  and,  drop  by  drop,  potash.  The  blue  precipitate 
first  produced  redissolves  in  the  excess  of  potash,  to  a  blue 
liquid,  which  deposits  suboxide  -of  copper  when  heated  (at 

*  See  foot-note  on  pase  154. 


MILK-SUGAR.       UREA.       PYROGALLIX.  153 

first  yellow  and  afterwards  red)  more  readily  than  in  the  case 
of  cane-sugar. 

Heat  a  portion  of  the  solid  substance  with  strong  sulphuric 
acid :  it  should  not  carbonize  so  readily  as  cane-sugar. 

Grape-sugar  is  much  less  sweet  than  cane-sugar.* 

181.  Milk-sugar,  C12H24O12,  identified. 

Very  much  less  sweet  than  either  cane-  or  grape-sugar. 

Feels  gritty  between  the  teeth.  Almost  insoluble  in 
ordinary  alcohol,  which  dissolves  cane-  or  grape-sugar  on 
heating. 

Answers  to  the  same  tests  as  grape-sugar. 

182.  Urea,  C2H4N2O2,  identified. 

Prismatic  crystals.  Resembles  nitre  in  appearance  and 
taste.  Very  soluble  in  water  and  alcohol. 

Heated  in  a  tube,  melts  easily,  and  evolves  much  ammonia. 

A  pretty  strong  aqueous  solution  of  urea,  stirred  with  con- 
centrated nitric  acid  in  excess,  and  allowed  to  stand,  deposits 
scaly  crystals  of  nitrate  of  urea. 

If  a  strong  solution  of  oxalic  acid  be  substituted  for  nitric 
acid,  crystals  of  oxalate  of  urea  are  deposited. 

If  a  solution  of  urea  be  mixed  with  a  solution  of  mercuric 
nitrate, t  a  white  precipitate  is  produced. 

On  adding  excess  of  silver  nitrate  to  solution  of  urea,  and 
boiling  down,  in  a  test-tube,  to  a  small  bulk,  a  crystalline 
precipitate  of  silver  cyanate  separates  on  cooling ;  if  this 
precipitate  be  heated  with  dilute  hydrochloric  acid,  it  effer- 
vesces, and  evolves  the  pungent  odor  of  cyanic  acid ;  on 
adding  potash,  and  boiling,  the  odor  of  ammonia  is  per- 
ceived. 

183.  Pyrogallic  acid  or  Pyrogallin,  C6H603,  identified. 
White    or   slightly    brown    crystalline    powder.       Often 

*  Sugar  of  fruits  (fructose  or  uncrystallizable  sugar)  answers  to 
the  same  taste  as  grape-sugar. 

f  Prepared  by  adding  finely-powdered  red  oxide  of  mercury  to 
hot  nitric  acid  as  long  as  it  is  dissolved. 


154  SALICINE.       ALBUMEN.       STARCH. 

collected  into  feathery  flakes.  Bitter.  Very  light.  Dis- 
solves easily  in  water,  alcohol,  and  ether. 

Potash  renders  it  intensely  brown,  oxygen  being  absorbed 
from  the  air. 

Sulphate  of  iron  (ferrous  sulphate)  colors  solution  of  pyro- 
gallic  acid  dark  blue. 

Perchloricle  of  iron  (ferric  chloride)  gives  a  fine  red  color 
with  solution  of  pyrogallic  acid. 

184.  Saticine,  C13H1S07,  identified. 

White  crystalline  powder.  Bitter.  More  soluble  in  alco- 
hol than  in  water.  Insoluble  in  ether.  Concentrated  sul- 
phuric acid  converts  it  into  a  blood-red  resinous  mass.  Its 
aqueous  solution,  boiled  for  some  time  with  hydrochloric 
acid,  yields  a  granular  precipitate  of  saliretine. 

185.  Soluble  albumen,  C72H112N18SO22,  identified. 
Yellowish  white  shining  scales.     Tasteless.     Assumes  the 

appearance  of  gum  in  cold  water.  Becomes  opaque  and 
insoluble  when  boiled  with  water.  The  solution  of  albumen 
in  cold  water  is  coagulated  by  boiling. 

Dilute  nitric  acid  precipitates  it. 

Perchloride  of  mercury  (corrosive  sublimate)  causes  a 
white  precipitate. 

186.  The  commonest  neutral  organic   substances  which 
are    not  dissolved  by  cold  water,*  but  dissolve  in  boiling 
water  are — 


Gelatine 


Gum 


Dextrine  or  British  gum 

Starch 

Oxalate  and  nitrate  of  urea. 


187.   Starch,  C6H10O5,  identified. 

White.     Tasteless.     Forms  a  paste  when  boiled  with  a 

*  It  must  be  remembered  that  this  is  not  a  very  exacting  dis- 
tinction ;  thus,  at  the  ordinary  temperature  of  the  laboratory,  dex- 
trine and  the  oxalate  and  nitrate  of  urea  dissolve  pretty  readily. 


DEXTRINE.   GUM.   GELATINE.  155 

small  quantity  of  water ;  even  with  much  water,  yields  a 
turbid  solution. 

Boiled  for  some  time  with  dilute  hydrochloric  acid,  the 
solution  becomes  thinner,  and  answers  to  the  tests  for  grape- 
sugar  (180). 

Solution  of  iodine  in  water,  added  to  the  (cold)  solution  of 
starch,  gives  a  fine  blue  color  which  disappears  on  boiling, 
and  returns  as  the  liquid  cools.  Potash  destroys  the  blue 
color. 

188.  Dextrine,  C6H10O5,  identified. 

Yellowish.    Tasteless.    Behaves  like  gum  with  cold  water. 

Boiled  for  some  time  with  dilute  hydrochloric  acid,  the 
solution  answers  to  the  tests  for  grape-sugar  (180). 

Solution  of  iodine  does  not  give  the  blue  color. 

Tribasic  acetate  of  lead. (or  ammoniacal  acetate  of  lead) 
does  not  precipitate  the  solution  of  dextrine,  which  is  thereby 
distinguished  from  ordinary  gum. 

Solution  of  tannic  acid  does  not  precipitate  dextrine,  which 
thus  differs  from  starch. 

189.  Gum,  C12H22OU,  identified. 

Answers  to  the  same  tests  as  dextrine,  but  its  solution  is 
precipitated  by  tribasic  acetate  (or  ammonia  calacetate)  of 
lead.  Gum  arabic  contains  lime,  which  may  be  detected  by 
oxalate  of  ammonia. 

190.  Gelatine  C41H6.N13O16,  identified. 

Tasteless.  Its  solution  in  hot  water  sets  to  a  jelly  on 
cooling.  Perchloride  of  mercury  (corrosive  sublimate)  pre- 
cipitates it.  Tannic  acid  precipitates  it. 

Evolves  very  offensive  alkaline  vapor  when  heated  in  the 
dry  state. 

191.  Soap  may  be  identified  by  the  directions  given  at 
pp.  85  and  90. 

192.  Oxalate  and  nitrate  of  urea  crystallize  readily  from 


156  UREA.       STEARINE. 

their  aqueous  solutions  on  cooling.  The  nitrate  evolves  a 
remarkably  pungent  smell  when  heated  in  a  small  tube. 

The  oxalic  and  nitric  acids  may  be  detected  by  the  tests 
given  in  Table  H. 

The  urea  may  be  detected  by  mercuric  nitrate  (182),  a 
little  potash  being  first  added. 

By  adding  carbonate  of  baryta  to  the  aqueous  solution, 
evaporating  to  dryness  on  a  water-bath  (231),  and  treating 
the  residue  with  alcohol,  the  urea  is  dissolved,  and  may  be 
obtained,  by  evaporation,  in  crystals  which  can  be  identified 
as  in  (182). 

If  a  solution  of  nitrate  or  oxalate  of  urea  be  mixed  with 
excess  of  silver  nitrate,  filtered  if  necessary,  sodium  carbonate 
added  till  a  slight  permanent  precipitate  appears,  boiled, 
filtered,  and  boiled  down  to  a  small  bulk  in  a  test-tube,  the 
liquid,  on  cooling,  deposits  silver  cyanate  which  may  be 
identified  as  at  (182). 

193.  The  commonest  of  these  organic  substances  which 
are  insoluble  in  water,  but  dissolve  in  hot  alcohol,  are — 


Stearine 
Palmitic  acid 
Rosin 


Stearic  acid 
Cholesterine 
Naphthaline. 


194.  Stearine,  C57H110O6,  identified. 

White.  Crystalline.  Fuses  in  water  heated  to  160°  F. 
(71°  C.).*  (See  194a.) 

Dissolves  in  boiling  alcohol,  but  not  with  extreme  facility ; 
deposited  again  on  cooling. 

Boiled  with  potash,  forms  at  first  a  milky  emulsion,  and 
gradually  dissolves,  yielding  a  solution  of  soap,  p.  85.  Heated 
on  platinum  or  porcelain,  evolves  the  characteristic  pungent 
fumes  of  acroleine,  and  burns  with  a  luminous  flame. 

*  One  modification  of  stearine  fuses  at  131°  F.  (55°  C.) 


CHOLESTERINE.       HOSIX.  157 

194#.  To  ascertain  the  exact  temperature  at  which  a  sub- 
stance fuses,  draw  out  a  piece  of  glass  tube  (Fig.  15,  p.  34) 
to  a  fine  tapering  point,  and  introduce  a  fragment  of  the  sub- 
stance to  be  tested.  Warm  the  tube  gently  so  that  the 
melted  substance  may  run  into  the  point,  where  it  will  be- 
come opaque  on  cooling.  The  tube  is  now  plunged,  together 
with  a  thermometer,  into  a  beaker  (Fig.  55)  of  water  slowly 
heated  over  a  lamp,  and  the  temperature  is  noted  at  which 
the  point  becomes  transparent,  in  consequence  of  the  fusion 
of  the  substance. 

195.  Steric  Acid,  HC18H35Oa,  identified. 

White.  Crystalline.  Fuses  in  water  heated  to  160°  F. 
(71°  C.).  (See  194a.)  Dissolves  very  easily  in  boiling 
alcohol ;  the  solution  reddens  litmus.  Potash  speedily  dis- 
solves it,  yielding  a  solution  of  soap  (191).  When  heated, 
it  does  not  evolve  the  pungent  fumes  of  acroleine.  It  burns 
with  a  luminous  flame. 

196.  Palmitic  Acid,  HC,6H31O2,  identified. 

White.  Crystalline.  Fuses  in  water  heated  to  144°  F. 
(62°  C.).  (See  194«.)  In  other  respects  resembles  stearic 
acid. 

197.  Cholesterine,  C26HUO,  identified. 

Transparent  tabular  crystals.  Infusible  even  in  boiling 
water.  Dissolves  easily  in  boiling  alcohol,  and  crystallizes 
out  in  rhombic  plates.  Not  changed  by  boiling  with  potash. 

Fuses  easily  when  heated  to  293°  F.,  and  passes  off'  in 
vapor,  which  burns  with  a  luminous  flame. 

Moistened  with  strong  nitric  acid,  and  evaporated  to'  dry- 
ness,  gives  a  yellow  residue  changed  red  by  ammonia. 

Moistened  with  strong  hydrochloric  acid,  a  little  perchlo- 
ride  of  iron  added,  and  evaporated  to  dryness,  assumes  a 
violet  blue  color. 

198.  Rosin  identified. 

Semi-transparent  yellow  or  brown  solid,  smelling  of  tur- 


158 


USE    OF    ETHER. 


pentine.     Dissolves  in  boiling  alcohol ;  the  solution  deposits 
small  crystals  of  (sylvic  acid,  HC^H^O^)  as  it  cools. 

Dissolves  in  boiling  potash,  and  is  reprecipitated  in  soft  solid 
flakes  by  hydrochloric  acid.  Fuses  easily  at  (2GO°  or  270° 
F.)  and  burns  with  a  very  smoky  flame. 

199.  Naphthaline,  C10H8,  identified. 

Transparent  flaky  crystals  smelling  strongly  of  coal-gas. 
Fuses  in  hot  water  at  174°  F.  (79°  C.)     (See  194a.) 
Burns  with  a  very  smoky  flame.     Not  changed  by  boiling 
with  potash.     Heated  in  a  dry  test-tube,  sublimes  in  crystals. 

200.  The  inflammability  of  ether  and  the  readiness  witli 
which  it  is  converted  into  vapor,  render  it  necessary  to  be 
very  careful  in  using  it. 

Never  bring  a  bottle  of  ether  within  two  or  three  feet  of  a 
flame.  Replace  the  stopper  immediately. 


Fid.  55. 


In  boiling  a  substance  with  ether? 
do  not  employ  a  flame,  but  place  the 
test-tube  in  some  hot  water,  and 
close  the  orifice  lightly  with  the  finger 
in  order  to  restrain  the  escape  of 
vapor  (fig.  55). 

201.  The  commonest  organic  sub- 
stances which  are  insoluble  in  water, 
and  sparingly  dissolved  by  alcohol, 
but  soluble  in  boiling  ether,  are — 


Palmitine 
Spermaceti  or  cetine 


Wax 

Paraffine. 


202.   Palmitine,  C51HggO6,  identified. 

White.  Crystalline.  Fuses  in  water  heated  to  145°  F. 
(63°  C.)*  (See  194a.) 

Behaves  in  other  respects  like  stearine  (194),  except  as  to 
its  solubility  in  alcohol. 


One  modification  of  palmatine  fuses  at  115O  F.  (46°  C.). 


SPERMACETI.       WAX.       PARAFFINE.  159 

203.  Spermaceti,   C32TIfil02,  identified. 
Characteristic   pearly  crystalline    appearance.      Fuses  in 

water  heated  to  120°  F.  (49°  C.).  (See  194«.)  Boiling 
with  potash  does  not  saponify  it.  Does,  not  evolve  the  pung- 
ent vapors  of  acroleine  when  heated,  thus  differing  from 
palmitine. 

204.  Wax  identified. 

White  or  yellow  ;  not  distinctly  crystalline.  Fuses  in  water 
heated  to  145°  or  150°  F.  (63°  or  66°  C.).  (See  194a). 

Boiled  with  alcohol,  is  partly  dissolved.  When  the  solu- 
tion cools,  cerotic  acid,  C27H54O2,  crystallizes  out,  which  fuses 
in  water  heated  to  174°  F.  (79°  C.).  The  alcoholic  solution 
reddens  litmus.  When  evaporated  on  a  water  bath,  it  leaves 
ceroleine,  a  greasy  substance  of  peculiar  odor,  fusible  at  83° 
F.  (28°  C.).  Wax  is  little  affected  by  boiling  with  potash. 

205.  Paraffine  identified. 

White.  Crystalline ;  resembles  spermaceti.  Fuses  in 
water  heated  to  112°  F.  (44°  C.).*  (See  194a).  Very 
sparingly  soluble  in  alcohol.  Unaffected  by  boiling  with 
potash.  May  be  distilled  with  little  decomposition,  which  is 
not  the  case  with  wax. 

206.  The  commonest  organic  substances  which  are   in- 
soluble in  boiling  water,  alcohol,  and  ether,  and  which  can- 
not be  distinguished  by  their  organized  structure, f  are — 

Albumen  |  Caseine. 

Albumen  and  Caseine,  in  their  coagulated  or  insoluble 
states,  so  nearly  resemble  each  other,  that  no  satisfactory  test 
can  be  given  by  which  they  may  be  distinguished. 

They  are  both  white  and  opaque  in  the  moist  state,  be- 
coming horny,  yellowish,  and  translucent  when  dried. 

*  Some  specimens  of  paraffine  fuse  at  149°  F.  (65°  C.). 

f  Such  substances  as  fibrin,  cellulose,  lignine,  hair,  silk,  wool, 
horn,  &c.,  would  always  be  recognized  without  having  recourse  to 
chemical  tests. 


160  ALBUMEN.       CASEINE. 

Dried  albumen  and  caseine,  placed  in  water,  slowly  soften, 
swell,  and  become  \vhite  and  opaque. 

Heated  in  a  tube,  they  carbonize,  swell  up,  and  emit  very 
offensive  vapors,  which  are  strongly  alkaline  to  reddened 
litmus  paper. 

Strong  nitric  acid  colors  them  bright  orange,  and  gradually 
dissolves  them  when  heated. 

Solution  of  nitrate  of  mercury,  prepared  by  dissolving  2 
parts  of  mercury  in  4  parts  of  nitric  acid  (sp.  gr.  1-40)  im- 
parts a  bright  red  color  to  albumen  and  caseine  (Millon's 
test). 

Potash  dissolves  albumen  and  caseine,  when  heated  ;  acetic 
acid,  gradually  added  to  the  solution,  causes  a  flocculent 
precipitate,  which  is  redissolved  by  an  excess  of  the  acid. 

If  albumen  or  caseine  be  boiled  with  potash,  and  a  few 
drops  of  solution  of  acetate  of  lead,  a  dark  precipitate  of 
sulphide  of  lead  is  produced. 

Strong  hydrochloric  acid  slowly  dissolves  albumen  and 
caseine  with  the  aid  of  heat,  yielding  solutions  which  have  a 
violet  color. 


LIQUID    ORGANIC    SUBSTANCES.       TABLE 


161 


£      V 
ll 


x  .3 

rv]     i. 

^ 
II 

O  ^ 


.  *  ^H 
c>   ^ 

?l 
1 


a 

.0    CM 


w 


Q 


«     03 


Ilf 

"-1 


I* 

8  a? 


.-y          f- 


162  ALCOHOL.       METHYLATED-SPIRIT. 


NOTES  TO  TABLE  Q. 

208.  The  commonest  liquid  organic  substances  (not  dis- 
tinguishable by  the  preceding  Tables)  which  have  a  distinct 
color,  and  mix  easily  with  water,  are — 


Alcohol 

Aldehyde 

Aceton 


Wood-spirit  (methylic  alcohol) 

Nicotine 

Butyric  acid. 


209.  Alcohol,  C2H6O,   or   Spirit  of  Wine   (which  is  a 
mixture  of  alcohol  and  water),  may  often  be  recognized  at 
once  by  its  odor. 

If  not  too  much  diluted,  it  inflames  readily,  and  burns 
with  a  pale  flame. 

If  much  water  be  present,  it  may  be  separated  either  by 
carbonate  of  potash  (226),  or  by  distillation  (227). 

When  alcohol,  even  in  a  diluted  state,  is  mixed  with  enough 
chromate  or  bichromate  of  potash  to  color  it  distinctly,  a 
little  hydrochloric  acid  added,  and  heat  applied,  the  red 
color  of  the  solution  is  changed  to  green,  in  consequence  of 
the  reduction  of  the  chromic  acid  to  chromic  oxide  by  the 
deoxidizing  effect  of  the  alcohol,  a  part  of  which  is  converted 
into  aldehyde,  distinguishable  by  its  peculiar  odor. 

By  heating  alcohol  with  some  slrong  sulphuric  acid,  and 
an  acetate  (either  acetate  of  potash,  soda,  or  lead),  the  very 
agreeable  odor  of  acetic  ether  is  developed. 

210.  Methylated-spirit  (a  mixture  of  spirit  of  wine  with 
wood-spirit)  may  be  distinguished  from  pure  spirit  of  wine 
by  its  odor,  and  by  the  brown  red  color  which  it  assumes 
when  mixed  with  strong  sulphuric  acid. 

211.  Wood  Naphtha,  C  H4O  (pyroligneous  ether,  pyroxylic 
spirit),  is  not  commonly  met  with  in  commerce  in  a  pure 
state,  in  which  form  it  bears  much  resemblance  to  ordinary 
alcohol.     The  ordinary  wood-naphtha  has  a  yellowish  color 
and  a  peculiar  nauseous  odor.     When    mixed  with  water, 


WOOD-SPIRIT.       ALDEHYDE.       NICOTINE.  163 

it  becomes  turbid,  from  the  separation  of  certain  oily  im- 
purities. 

Wood-naphtha  burns  with  a  pale  flame,  resembling  that  of 
alcohol. 

Potash  immediately  imparts  a  brown  color  to  wood- 
naphtha,  an  effect  not  produced  with  alcohol  until  some  time 
has  elapsed. 

212.  Acetone,  C3H6O  (wood-spirit),  may  be  recognized 
by  its  peculiar  odor  (which  may  be  ascertained  by  heating 
solid  acetate  of  lead   in  a  small  tube).     It  differs  also  from 
alcohol  and  wood-naphtha  by  burning  with  a  very  luminous 
flame. 

213.  Aldehyde,  C2H4O,  has  a  very  peculiar  acrid  apple- 
like  smell  which  affects  the  eyes.     When  exposed  to  the  air 
it  passes  off  in  vapor  much  more  readily  than  alcohol,  wood- 
naphtha,  or  acetone,  first  becoming  acid  from  absorption  of 
oxygen. 

If  aldehyde  be  added  to  nitrate  of  silver  mixed  with  a 
very  little  ammonia,  the  metal  is  reduced  on  the  application 
of  heat,  and  forms  a  mirror-like  coating  upon  the  side  of  the 
tube.  Potash  imparts  a  brown  color  to  aldehyde.  Alde- 
hyde is  very  inflammable,  and  burns  with  a  pale  flame. 

214.  Nicotine,  C10H14N2,  is  an  oily  liquid,  tinged  brown 
by  exposure  to  air,  and  having  a  powerful  odor  of  tobacco. 

Its  aqueous  solution  is  strongly  alkaline  to  test-papers. 
When  the  aqueous  solution  is  acidulated  with  hydrochloric 
acid,  mixed  with  bichloride  of  platinum,  and  allowed  to  stand, 
it  deposits  a  precipitate  composed  of  very  distinct  prismatic 
crystals. 

Nicotine  is  inflammable,  and  burns  with  a  smoky  flame. 

215.  Butyric  Acid  HC4H7O2,  is  a  colorless  liquid,  having 
a  most  powerful  smell  of  rancid  butter.     It    is   somewhat 
lighter  than  water,  in  which  it  dissolves  when  shaken.     If 
strong  hydrochloric  acid  be  added  to  the  aqueous  solution, 
the  butyric  acid  separates  again  as  an  oil  upon  the  surface. 


164          BUTYRIC    ACID.       ANILINE    OR    PHENYLAMINE. 

When  butyric  acid  is  shaken  with  alcohol  and  oil  of  vitriol, 
butyric  ether  is  formed,  which  is  recognized  by  its  odor  of 
pine-apple. 

216.  The  commonest  liquid  organic  substances  (not  dis- 
tinguishable by  the  preceding  Tables)  which  have  a  distinct 
odor,  do  not  mix  easily  with  water,  but  are  miscible  with 
potash,  are — 

Carbolic  acid  (in  its  liquid  form)    |          Valerianic  acid. 

21*7.  Liquid  Carbolic  Acid  is  usually  met  with  as  a 
brownish  or  brown  liquid,  having  a  powerful  smell  of  tar. 
When  poured  into  water,  it  sinks  to  the  bottom. 

It  may  be  further  examined  as  at  (176). 

218.  Valerianic  Acid,  HC5H9O2,  is  a  colorless  oily  liquid, 
which  floats  upon  water,  and  has  a  powerful  odor  resembling 
that  of  valerian  root. 

219.  Aniline  C6H7N,  is  usually  met  with  as  a  yellowish 
or  brown  oily  liquid,  having  a  strong  smell  recalling  that  of 
ammonia.     It  sinks  in  water. 

Solution  of  chloride  of  lime  added  in  excess  to  a  drop  of 
aniline  shaken  with  water  produces  an  intense  purple  color, 
If  toluidine  be  present,  as  is  generally  the  case  with  commer- 
cial aniline,  the  purple  color  passes  into  brown  ;  but  if  the 
mixture  be  shaken  with  ether,  the  latter  will  rise  to  the 
surface,  carrying  a  red-brown  coloring  matter  with  it,  and 
leaving  the  solution  of  a  fine  blue  color.  Deal  is  stained 
yellow  by  aniline. 

Oxalic  acid  combines  with  aniline  to  form  a  sparingly 
soluble  oxalate. 

Corrosive  sublimate  (mercuric  chloride)  in  the  solid  form, 
heated  with  aniline,  converts  it  into  a  dark  purple  mass 
which  yields  a  purple-red  solution  in  alcohol. 


ETHER.       CHLOROFORM.  165 

220.  The  commonest  liquid  organic  substances  (not  dis- 
tinguishable by  the  preceding  Table)  which  have  a  distinct 
odor  and  do  not  mix  easily  with  water,  potash,  or  hydro- 
chloric acid,  are — 


Ether 

Chloroform 

Benzole 


Oil  of  bitter  almonds 
Nitrobenzole 
Bisulphide  of  carbon. 


221.  Ether,  C4H10O,  may  be  identified  almost  with  cer- 
tainty by  its  odor.     It  is  colorless,  very  easily  inflammable, 
and  burns  with  a  bright  flame.     Ether  very  easily  passes  off 
in  vapor  when  exposed   to  the  air,  so  that  when   the  mouth 
of  a  test-tube  which  contains  ether  is  applied  to  a  light  the 
vapor  takes  fire,  and  burns  at  the  mouth  of  the  tube  if  the 
latter  be  slightly  inclined. 

Ether  boils  at  a  temperature  (94°.8  F.,  35°  C.)  which 
feels  scarcely  warm  to  the  hand. 

Oil  or  fat  of  any  kind  dissolves  very  easily  in  ether. 

222.  Chloroform,  CHC13,  is  a  colorless,  very  fragrant 
liquid,  which  sinks  in  water  (sp.  gr/1.5). 

It  easily  escapes  in  vapor  when  exposed  to  air,  and  boils 
at  142°  F.  (61°  C.). 

Chloroform  dissolves  India-rubber  with  great  facility. 

When  chloroform  is  gently  heated  with  a  solution  of 
hydrate  of  potash  in  alcohol  it  yields  chloride  of  potassium 
and  formiate  of  potash.  The  former  may  be  recognized  by 
the  white  precipitate  with  nitrate  of  silver,  insoluble  in  nitric 
acid,  and  the  latter  by  neutralizing  the  alkaline  liquid  with 
dilute  sulphuric  acid,  adding  an  excess  of  nitrate  of  silver, 
decanting  the  liquid  from  the  precipitate,  and  gently  heat- 
ing it,  when  metallic  silver  will  be  separated  as  a  dark 
precipitate,  either  at  once  or  on  adding  a  drop  or  two  of 
ammonia. 

The  tests  for  ascertaining  the  purity  of  the  chloroform 
employed  in  surgical  operations,  are  the  following: — 


166       BITTER    ALMOND    OIL.       NITROBENZOLE.       BENZOLE. 

It  should  be  quite  free  from  any  odor  of  chlorine. 

When  shaken  with  water,  the  solution  should  not  redden 
blue  litmus  paper,  or  produce  any  turbidity  with  nitrate  of 
silver. 

When  shaken  with  oil  of  vitriol,  the  mixture  should  re- 
main colorless. 

On  evaporating  a  little  chloroform  on  the  hand  it  should 
not  leave  any  unpleasant  odor. 

233.  Oil  of  Bitter  Almonds,  C7H6O2,  has  a  very  charac- 
teristic smell,  a  yellowish  color,  and  sinks  in  water. 

When  heated  with  solid  hydrate  of  potash  it  yields  ben- 
zoate  of  potash.  If  the  cool  mass  be  dissolved  in  water,  and 
hydrochloric  acid  added  to  the  solution,  benzoic  acid  is 
precipitated  (154). 

As  sold  in  the  shops,  the  oil  of  bitter  almonds  is  often 
dissolved  in  spirit  of  wine,  from  which  it  is  separated  on 
adding  water. 

224.  Nitrobenzole,  C6H5NO2,  or  Essence  of  Mirlane, 
much   resembles   oil   of  bitter  almonds  in  appearance  and 
odor,  but  may  be  easily  distinguished  from  it  by  converting 
it  into  analyne. 

For  this  purpose  the  nitrobenzole  is  dissolved  in  alcohol, 
some  hydrochloric  acid  added,  and  a  fragment  of  granulated 
zinc.  When  the  evolution  of  hydrogen  has  nearly  ceased, 
the  liquid  is  mixed  with  excess  of  potash  and  shaken  with 
ether,  which  dissolves  the  aniline.  When  the  ether  has  risen 
to  the  surface,  it  is  poured  off  into  a  small  dish  and  allowed 
to  evaporate  spontaneously,  when  the  aniline  will  remain, 
and  may  be  identified  as  at  (219). 

225.  Benzole,  C6H6,  or  Benzine,  or  Benzene,  is  a  color- 
less liquid  which  smells  strongly  of  coal-gas. 

It  floats  on  water,  is  very  inflammable,  and  burns  with  a 
luminous  smoky  flame. 


SEPARATION    OF    ALCOHOL    FROM    WATER.  167 

When  added,  drop  by  drop,  to  the  strongest  nitric  acid, 
benzole  is  dissolved,  with  evolution  of  much  heat  and  red 
fume,  to  a  red  liquid,  and  if  this  be  poured  into  a  large 
volume  of  water,  a  heavy  oil  is  separated,  which  is  nitroben- 
zole,  and  may  be  identified  as  described  above  (224). 

Bisulphide  of  Carbon,  CS2,  is  a  colorless  or  yellowish 
liquid,  which  sinks  in  water  and  has  a  most  offensive  smell.* 
It  is  extremely  inflammable,  and  burns  with  a  blue  flame, 
emitting  a  powerful  odor  of  sulphurous  acid.  If  a  few  drops 
be  placed  in  a  watch-glass,  and  blown  upon,  it  will  evaporate 
very  rapidly,  condensing  the  moisture  upon  the  glass  into 
white  hoar-frost,  and  freezing  a  part  of  the  bisulphide  to  a 
white  crystalline  mass. 

226.  Removal  of  water  from  alcohol  by  carbonate  of 
potash. — Pour  the  liquid  into  a  large  test-tube,  or  a  draught- 
bottle  furnished  with  a  good  cork,  so  that  the  tube  or  bottle 
may  be  about  half-filled.    Introduce  dried  powdered  carbonate 
of  potash,  in  small  portions,  shaking  well  after  each  addition, 
as  long  as  it  dissolves  in  the  liquid.  •   If  alcohol  be  present, 
it  will  form  a  separate  layer  upon  the  surface  of  the  solu- 
tion of  carbonate  of  potash  in  water.     Pour  off  this  layer 
carefully  into  another  tube,  and  dip  a  glass-rod  in  it  to  test 
its  inflammability.     It  m..y  then  be  examined  by  other  tests 
for  alcohol. 

227.  Separation  of  alcohol  and  water  by  distillation 

To  separate  alcohol  from  water  by  distillation,  the  mixture 
must  be  maintained  for  some  time  at  a  temperature  below 
212°  F.  (100°  C.),  when  the  alcohol  wall  rise  in  vapor  much 
more  readily  than  the  water,  and  if  the  first  portions  of  vapor 
be  condensed  and  collected  in  another  vessel,  they  will  be 
found  to  contain  the  chief  part  of  the  alcohol. 

*  Purified  bisulphide  of  carbon  has  not  an  offensive  odor. 


168  DISTILLATION. 

DISTILLATION — The  best  form  of  apparatus  for  distillation 
is  that  represented  in  fig.  57,  where  a  represents  a  Retort, 
through  the  tubulus  (&)  of  which  a  thermometer*  (c)  is  fixed 
by  means  of  a  perforated  cork  (228)  so  that  the  bulb  of  the 
thermometer  nearly  touches  the  bottom  of  the  retort.  The 
neck  of  the  retort  is  thrust  into  the  inner  tube  (e?)  of  a  Liebig*s 
condenser,  through  the  outer  tube  (e)  of  which  a  constant 
flow  of  water  is  maintained  by  means  of  the  pipes  (/)  (which 
comes  from  the  tap)  and  (g)  (which  runs  into  the  sink). 
These  pipes  are  vulcanized  India-rubber,  and  (y)  is  slipped 
on  to  a  piece  of  gas-pipe  or  glass  tube  (h)  bent  into  a  hook, 
so  as  to  hang  upon  the  funnel  (i).  The  joint  (&),  where  the 
retort  neck  is  fitted  into  the  condensing  tube,  is  secured  by  a 

FIG.  56.  Fia.  57. 


Distillation. 

tight  bandage  made  by  warming  a  piece  of  sheet  india- 
rubber  about  four  inches  long  and  one  broad,  securing 
one  end  of  it  with  the  thumb  over  the  joint,  and 
stretching  it  very  considerably  whilst  binding  it  round 
the  tubes  (fig.  58).  The  condensed  liquid  drops  into 
the  bottle  (m),  which  may  be  changed  when  necessary 
without  disturbing  the  apparatus. 


Thermo- 
meter. 


flip  t.lip.rninTnetttr  adapted  for  this  Duroose. 


DISTILLATION. 

FIG.  58. 


1G9 


Heat  is  gradually  applied  to  the  FIG.  59. 

retort,  either  by  a  rose  gas  burner 
(fig.  59),  or  a  plain  ring  burner 
(fig.  60),  or  an  Argand  burner  with 
a  chimney  (fig.  32,  p.  94). 

Since  alcohol  boils  at  173°  F. 
(78°-3  C.),  a  rough  estimate  of  the 
proportion  of  alcohol  present  may 
be  formed  from  the  quantity  of 
liquid  which  distils  over  at  a  few 
degrees  above  that  temperature,  and 
the  distillation  may  be  stopped 

when  the  thermometer  approaches  212°  F.  (100°  C.)  and  the 
taste  and  smell  of  the  liquid  distilling  over  (distillate}  indi- 
cate the  presence  of  very  little  alcohol. 

Where  such  an  apparatus  as  that  just  described  is  not  to 
be  obtained,  some  simpler  contrivance  must  be  substituted 
for  it. 


Hose  Burner. 


170  DISTILLATION. 

A  plain  retort  («,  fig.  60)  with  a  long  neck  may  be  em- 
ployed, and  any  common  bottle  (b)  will  serve  for  a  receiver. 


Distillation. 

To  promote  condensation,  a  long  strip  of  filter-paper  (c)  may 
be  wetted  and  wrapped  smoothly  round  the  neck,  a 
string  of  wet  tow  (d)  being  passed  twice  round  the 
neck  at  the  lower  edge  of  the  paper,  and  twisted 
tightly  into  a  tail  to  carry  off  the  water,  which  may 
either  be  gently  poured  from  time  to  time  upon  the 
upper  part  of  the  paper,  or  allowed  to  trickle  slowly 
from  a  funnel  (e),  the  neck  of  which  is  partly  stopped 
with  tow.  A  tube  funnel  (fig.  61)  is  employed  for 
introducing  the  liquid  into  the  retort  without  soiling 
the  neck. 

A  flask  with  a  bent  tube  (229),  tightly  fitted  into 
it  with  a  perforated  cork   (228),  may  be  employed 
Tube,     instead  of  a  retort.     One  limb  of  this  tube  may  be  20 

funnel.  * 

or  30  inches  long,  to  insure  condensation,  or  it  may 
be  adapted,  either  by  a  perforated  cork  or  a  caoutchouc 
bandage,  to  a  wider  tube  of  considerable  length  (fig.  62). 
A  convenient  support  for  this  tube  is  made  by  fixing  a  per- 


TO    PERFORATE    CORKS. 


171 


forated  bung  into  the  ring  of  a  retort-stand  turned  round 
into  the  required  position. 


FIG. 


228.    To  perforate  corks Smooth  cylindrical  holes  are 

made  in  corks  with  rat' s-tail  files  (fig.  63),  beginning  with  a 

FIG.  63. 


FIG.  64. 


Rat's-tail  file. 

small  size,  and  employing  the  larger  files  as  may  be  neces- 
sary. Corks  should  always  be  kept  on  the  points  of  the  files 
when  not  in  use,  as  the  steel  is  very  brittle. 

A  set  of  brass  cork  borers  of 
various  sizes  (fig.  65)  will  save 
much  time.  They  are  made  to  slip 
into  each  other,  and  are  provided 
with  a  steel  rod  (fig.  64)  which 
serves  as  a  handle  and  for  thrusting  out  the  cylinders  of  cork 
punched  by  the  borers.  A  cork-borer  is  selected  of  some- 
what less  diameter  than 
the  tube  for  which  the 
hole  is  to  be  bored, 
and  the  rod  is  thrust 
through  the  holes  in  the 
head  of  the  borer.  The 
cork  is  held  firmly 
against  the  wall  or  the 


Fia.  65. 
Set  of  cork-borers. 


FIG.  66. 


172 


BENDING    GLASS    TUBES. 


and  the  borer  worked  straight  into  it,  like  a  gimlet,  until  it  is 
about  half  way  through  the  cork.  The  borer  being  with- 
drawn, and  cleared,  if  necessary,  with  the  rod,  the  cork  is 
reversed,  and  bored  in  the  opposite  direction,  so  that  the  two 
holes  may  meet  in  the  centre,  and  form  a  perfectly  smooth 
cylindrical  passage,  which  is  very  carefully  enlarged  with 
a  rat's-tail  file  until  it  is  just  large  enough  to  receive 
the  tube,  which  should  pass  through  it  with  considerable 
friction. 

In  fitting  corks  air-tight  they  should  be  carefully  selected 
as  free  from  flaws  as  possible,  especially  at  the  ends.  The 
cork  should  be  somewhat  too  large  to  enter  the  mouth  of  the 
vessel  until  it  has  been  softened  by  rolling  it  heavily  on  the 
table  with  the  palm  of  the  hand,  or,  in  the  case  of  large  corks, 
under  the  sole  of  the  boot.  Corks  are  always  to  be  preferred 
to  bungs  or  shives. 

Vulcanized  India-rubber  stoppers  are  often  substituted  for 
corks,  and  are  decidedly  preferable  in  a  great  many  cases. 
They  may  be  perforated  with  the  cork-borers  described 
above,  which  should  be  dipped  in  spirit  of  wine. 

229.    To  bend  glass  tubes — Small  tubing  may  be  bent 

either  in  the  flame  of 
a  spirit-lamp,  or  in 
the  upper  part  of  a 
somewhat  flaring  gas- 
flame  (fig.  67).  The 
tube  should  be  slowly 
rotated,  and  moved  to 
and  fro  in  the  flame 
until  soft  enough  to 
be  bent,  which  should 
be  effected  by  a  gen- 
tle equal  pressure 
with  both  hands, 
care  being  taken  so 
to  regulate  the  soft- 


FIG.  67. 


Bending  glass  tube. 


SPIRIT    BLOWPIPE. 


173 


Fia.  68 


en  ing  of  the  glass  as  to 
obtain  a  nice  curve  (fig- 
68)  instead  of  a  sharp 
angle  (fig.  69).  Any  soot 
which  has  been  deposit- 
ed from  the  flame  may 
be  wiped  off  with  paper 
when  the  tube  is  cool. 

Large  tubing  is  more 
difficult  to  bend,  and  it 
is  often  necessary  to  em- 
ploy a  blowpipe  flame.      The  bend  must  be  annealed  by 
withdrawing  it  very  gradually  from  the  heat. 

The  gas  blowpipe  represented  in  fig.  70  is  very  convenient 
for  such  purposes,  especially  if  connected  with  a  double-action 
bellows  worked  by  the  foot. 


FIG.  69. 


Fia. 70. 


Fia.  71. 


Gas  blowpipe. 


Spirit  blowpipe. 


Where  gas  is  not  to  be  had,  a  spirit  blowpipe-lamp  is  some- 
times used.  That  represented  in  fig.  71  answers  the  purpose 
very  well.  A  small  quantity  of  spirit  (either  methylated 
spirit  of  wine  or  wood- naphtha)  burnt  inside  the  vessel  a 
vaporizes  the  spirit  in  the  space  b  between  the  walls  ;  the 
vapor  issuing  from  the  jet  c,  burns  with  a  powerful  flame. 
These  lamps  are  not  free  from  danger  in  consequence  of  a 
particle  of  cork  getting  into  the  spirit  and  obstructing  the 


174  GLYCERINE.       LACTIC    ACID.       OLEIC    ACID. 

jet,  when  the  operator  should  at  once  place  the  cover  on  the 
lamp,  and  thus  extinguish  the  flame. 

230.  If  the  liquid  has  no  powerful  or  characteristic  odor 
it  may  be — 

Glycerine  t  Lactic  acid 

Oleine  Oleic  acid. 

231.  Glycerine,  C3H8O3,  is  a  syrupy  liquid  which  has  an 
intensely  sweet  taste  and  mixes  readily  with  water. 

Flo  72  Heated  sharply  on  a  knife-blade  or  a 

piece  of  platinum  foil,  it  burns  with  a 
luminous  flame.     No  residue  is  left. 

When  heated  with  strong  sulphuric 
acid,  it  blackens  and  evolves  verv 
pungent  vapors  of  acroleine,  which 
strongly  affect  the  eyes. 

The  same  substance  is  produced  by 
heating  a  little   bisulplmte   of  potash 
moistened  with  glycerine. 
Placed  in  an  evaporating  dish  heated  upon  a  water-bath 
(fig.    72),   glycerine    suffers    no   perceptible    diminution    or 
change,  whilst   ordinary  syrup,   which   it  much  resembles, 
gradually  deposits  crystals  of  sugar  at  the  edge  of  the  liquid. 

232.  Lactic  acid,  HC3H.O3,  is  a  syrupy  liquid  which  has 
a  strong  acid  taste  and  readily  mixes  with  water. 

It  is  not  changed  by  heating  on  the-  water-bath  (fig.  72). 
If  it  be  diluted  with  water,  and  boiled  with  metallic  zinc, 
the  solution,  on  cooling,  deposits  crystalline  crusts  of  lactate 
of  zinc. 

When  lactic  acid  is  heated  in  a  retort,  several  products  are 
distilled  over,  and  among  them  a  crystalline  solid  known  as 
lactide,  C3H4O2,-which  is  soluble  in  hot  strong  alcohol,  and  is 
deposited  in  transparent  flat  prismatic  crystals  on  cooling. 

233.  Oleine,   C57H104O6,  and   oleic  acid,  HC13H33O2,  are 
colorless  or  yellow  oils  which  do  not  mix  with  water,  but 
float  upon  its  surface. 


EXAMPLES    FOR    PRACTICE. 


175 


Alcohol  dissolves  oleic  acid  more  readily  than  oleine. 

Ether  dissolves  them  botli  very  readily. 

Solution  of  potash  dissolves  oleic  acid  more  easily  than  it 
dissolves  oleine. 

Oleine  when  strongly  heated  evolves  the  odor  of  aeroleine, 
which  is  not  produced  when  oleic  acid  is  heated. 

If  a  test-tube  containing  oleic  acid  is  placed  in  melting  ice 
the  oleic  acid  solidifies  to  a  mass  of  needle-like  crystals,  but 
oleine  remains  liquid.  When  oleic  acid  has  been  kept  for 
some  time  in  contact  with  air  it  acquires  a  brown  color  and 
an  acid  reaction.  It  does  not  then  solidify  at  the  melting- 
point  of  ice. 

234.  Examples  for  Practice  in  Exercise  X. — Since  it 
is  only  by  a  careful  study  of  individual  organic  substances 
that  the  analyst  can  learn  to  identify  them  with  certainty, 
the  student  is  recommended  to  examine  as  many  of  the  sub- 
stances mentioned  in  this  Exercise  as  he  is  able  to  procure. 
A  list  of  them  is  subjoined. 


Acetone 

Ether 

Palmitic  acid 

Albumen  (white  of 

Gelatine 

Palmitine 

egg) 

Glycerine 

Paraffine 

Alcohol 

Grape-sugar 

Picric    or    carbazotic 

Aldehyde 

Gum  arable 

acid 

Aniline 

Indigo 

Pyrogallic  acid 

Benzole 

Lactic  acid 

Rosin 

Butyric  acid 

Methylated  alcohol 

Salicine 

Cane-sugar 

Milk-sugar 

Soap 

Caramel 

Naphthaline 

Spermaceti 

Carbolic  acid 

Nicotine 

Starch 

Caseine     (curd      of 

Nitrate  of  urea 

Stearic  acid 

milk) 

Nitrobenzole 

Stearine 

Chloral  hydrate 

Oil  of  bitter  almonds 

Urea 

Chloroform 

Oleic  acid 

Valerianic  acid 

Cholesterine 

Oleine 

Wax 

Dextrine 

Oxalate  of  urea 

Wood-naphtha. 

176 


ORGANIC    SUBSTANCES    EXAMINED. 


EXERCISE  XI. 

235.  EXAMINATION  OF  A  SOLID  ORGANIC  SUBSTANCE 
ABOUT  WHICH  NOTHING  IS  KNOWN  BUT  THAT  IT  IS  A  SlN- 
GLE  SUBSTANCE  AND  NOT  A  MIXTURE. 

The  analyst  is  recommended  to  mark  off  each  substance 
from  the  subjoined  list  as  it  is  excluded  by  his  experiments, 
and  in  this  way  to  reduce  the  number  of  possible  substances 
within  very  narrow  limits  : — 


Acetates 

Albumen 

Aniline  salts 

Benzoates 

Ben  zoic  acid 

Brucine 

Caffeine 

Cane-sugar 

Caramel 

Carbolic  acid 

Caseine 

Cholesterine 

Cinchoniiie 

' '         sulphate 
Citrates 
Citric  acid 
Cyanides 
Dextrine 
Ferridcyanides 
Ferrocyanides 
Gallic  acid 
Gelatine 
Grape-sugar 
Gum 

Hipp  uric  acid 
Indigo 
Malic  acid 
Meconic  acid 
Milk-sugar 
Morphine 

"         acetate 

"         hydrochlorate 

"         meconate 
Naphthaline 


Narcotine 
Nitroprussides 
Oxalates 
Oxalic  acid 
Palmitic  acid 
Palmitine 
Paraffine 
Picric  acid 
Prussian  blue 
Pyrogailic  acid 
Quinine 

"         and  iron,  citrate 
"         sulphate 
Rosin 
Salicine 
Soap 

Spermaceti 
Starch 
Stearic  acid 
Stearine 
Strychnine 
Succinic  acid 
Sugar 

Sulphocyanides 
Tannic  acid 
Tartaric  acid 
Tartrates 
Urates 
Urea 

"     nitrate 

"     oxalate 
Uric  acid 
Wax. 


ORGANIC    SUBSTANCES    EXAMINED, 


177 


A.  Heat  the  substance  gradually  in  a  small  glass  tube  (17). 
(a)  It  fuses  easily,  becoming  perfectly  liquid. 


Albumen 
Caseine 


EXCLUDES. 

Dextrine 
Starch 


Urates 
Uric  acid. 


(b)  It  passes  off  in  vapor 

(with  or  without  previous  fusion) 

and  leaves  no  black  (carbonaceous')  residue. 


EXCLUDES 


Albumen 

Caramel 

Caseine 

Cinchonine  and  its  salts 

Citric  acid  and  citrates 

Dextrine 

Gallic  acid 

Gelatine 

Gum 


Morphine  and  its  salts 

Quinine  and  its  salts 

Salicine 

Starch 

Strychnine  and  its  salts 

Sugar 

Tannic  acid 

Tartaric  acid  and  tartrates 

Uric  acid  and  urates. 


(c)  It  passes  off  in  vapor,  leaving  no  residue  whatever. 

EXCLUDES 

all  the  substances  in  the  above  list,  and,  in  addition, 
all  metals  except  mercury,  arsenic,  and  ammonium, 
(c?)  It  emits  vapors  which  have  the  odor  of  Ammonia, 
and  change  red  litmus  paper  to  blue. 

PROBABLE  PRESENCE  OF 


Ammonia,    combined  with   an 

organic  acid 
Urea 
Uric  acid 
A  ferrocyanide 
A  cyanide 
A  sulphocyanide 
A  ferridcyanide 


Gelatine 

Albumen 

Caseine 

Morphine 

Quinine 

Cinchonine 

Stry  ch  nine 

Aniline. 


The  analyst  should  mark  off  such  of  these  as  have  been 
excluded  by  the  previous  experiments. 


178 


ORGANIC    SUBSTANCES    EXAMINED. 


If  the  evolution  of  ammonia  is  abundant  and  unat- 
tended by  any  carbonization,  either  urea  or  one 
of  its  salts  is  probably  present  (182,  192). 

B.  Heat  the  substance  on  a  piece  of  porcelain,  and  continue 

the  heat  until  no  further  change  is  perceptible,  direct- 
ing the  outer  blowpipe-flame  upon  it  if  necessary,  to 
burn  off  the  carbon. 
(a)  No  residue  is  left. 

EXCLUDES 

all  metals  except  mercury,  arsenic,  and  ammonium, 
(i)  A  residue  is  left,  which  is  strongly  alkaline  to 
moistened  red  litmus  paper. 

PROBABLE  PRESENCE  OF 

an  Organic  Acid,  in  combination  with  Potash,  Soda, 
Baryta,  Strontia,  or  Lime. 
(See  Table  K.) 

C.  Shake  a  little  of  the  substance  with  cold  water,*  in  a 
test-tube. 

(«)  It  dissolves  easily. 

EXCLUDES 


Albumen 

Palmitine 

Benzoic  acid  (free) 
Brucine 
Caffeine 

Paraffine 
Quinine  (free) 
Rosin 

Caseine 

Salicine 

Cholesterine 
Cinchonine  (free) 
Dextrine  (?) 
Gallic  acid  (free) 
Gelatine 
Gum 

Spermaceti 
Starch 
Stearic  acid  (free) 
Stearine 
Strychnine  (free) 
Urates 

Hippuric  acid  (free) 
Morphine  (free) 
Karoo-tine 

Urea  nitrate  (?) 
"     oxalate  (?) 
Uric  acid. 

Palmitic  acid  (free) 

*  See  foot-note  on  page  154. 


ORGANIC    SUBSTANCES    EXAMINED.  179 

6)  It  does  not  dissolve. 

Boil  it  with  the  water ;  should  it  dissolve,  this 


Albumen 

Casein  e 

Palmitic  acid  (free) 


EXCLUDES 

Palmitine 
Paraffine 

Spermaceti 


Stearic  acid  (free) 

Stearine 

Wax. 


D.  Very  cautiously  taste  a  particle  of  the  substance. 

(«)  Its  taste  is  acid. 

Examine  for  an  organic  acid  by  Table  K,  and  for  an 

inorganic  acid  by  Table  G. 
(b)  Its  taste  is  bitter  ;  pass  on  to  F. 

E.  If  the  substance  does  not  dissolve  readily  in  water,  but 

dissolves  on  adding  a  little  potash,  and  is  precipitated 
by  the  addition  of  hydrochloric  acid — 

Examine  especially  for 

Benzoic  acid  (154)  |  Hippuric  acid  (156) 

Uric  acid  (161) 

F.  Dissolve  a  little  of  the  substance  in  water,  or  in  a  little 

dilute  hydrochloric  acid,  and  test  with  a  solution  of 
iodine  in  iodide  of  potassium. 

If  a  brown  precipitate  is  obtained,  examine  for  an  alka- 
loid by  Table  O. 

If  a  yellow  precipitate  is  produced,  examine  for  acetate 
of  lead  (p.  29). 

If  a  blue  precepitate  is  produced,  examine  for  starch 
(187). 

If  the  iodine-solution  is  bleached,  examine  for  a  cyanide 
(99). 


180  LIQUID    ORGANIC    SUBSTANCES    EXAMINED. 


EXERCISE  XII. 
236.  EXAMINATION  OF  A  LIQUID  ORGANIC  SUBSTANCE 

ABOUT    WHICH    NOTHING    IS    KNOWN,    BUT     THAT    IT     IS     A 

SINGLE  SUBSTANCE  AND  NOT  A  MIXTURE. 

A.  Ascertain  whether  it  has  any  odor  or  taste  characteristic 
of 


Acetic  acid  (149) 
Acetone  (212) 
Alcohol  (209) 
Aldehyde  (213) 
Aniline  (219) 
Benzole  (225) 


Bitter  almond  oil  (223)  j 
Butyric  acid  (215) 
Carbolic  acid  (217) 
Chloroform  (222) 
Ether  (221) 


Glycerine  (231) 
Nicotine  (214) 
Nitrobenzole  (224) 
Sugar  (179-181) 
Valerianic  acid  (218) 


Fomic  acid  (150)  |  Wood-naphtha  (2J1). 


B.  Evaporate  a  little  of  the  liquid  in  a  porcelain  dish,  care- 

fully observing  any  odor  which  may  be  developed,  and 
stopping  the  evaporation  as  soon  as  the  liquid  has  dis- 
appeared.* 

(a)  If  no  residue  is  left — 

The  liquid  probably  contains  one  of  the  above-men- 
tioned substances  recognizable  by  their  odor,  or 
possibly  glycerine  (231),  or  lactic  acid  (232). 

(b)  If  an  oily  inflammable  residue  is  left — 

Examine  especially  for — 
Oleine  (233)  |  Oleic  acid  (233). 

(c)  If  a  solid  residue  is  left — 

Evaporate  a  large  quantity  of  the  liquid  and  examine 
the  residue  according  to  (235). 

C.  Whilst  the  evaporation  is  proceeding,  the  analyst  should 

examine  another  portion  of  the  liquid  by  Tables  L,  O,  Q. 

*  Should  time  permit  it,  it  is  well  to  evaporate  over  a  steam-bath. 


UNKNOWN    LIQUIDS    EXAMINED.  181 

EXERCISE  XIII. 

237.  EXAMINATION  OF  A  SOLID  SUBSTANCE  OF  WHICH 
NOTHING  IS  KNOWN,  BUT  THAT  IT  IS  A  SlNGLE  SUBSTANCE, 

AND  NOT  A  MIXTURE. 

A.  Heat  a  little  of  the  substance  on  a  piece  of  porcelain,  and 

observe  whether  there  is  any  carbonization  or  peculiar 
odor  to  indicate  the  presence  of  organic  matter.* 

B.  Heat  another  portion  of  the  substance  with  strong  sul- 

phuric  acid,    and  observe  whether   any  carbonization 
indicative  of  organic  matter  takes  place. 

(a)  If  organic  matter  is  detected,  the  substance  must 

be  examined,  according  to  (235). 

(b)  If  no  organic  matter  is  detected,  the  substance  may 

be  examined,  according  to  Tables  A  to  I,  or  by 
the  blowpipe,  according  to  Tables  R  to  Z. 


EXERCISE  XIV. 

238.  EXAMINATION  OF  A  LIQUID  OF  WHICH  NOTHING 
IS  KNOWN  BUT  THAT  IT  IS  A  SOLUTION  OF  A  SlNGLE  SuB- 
STANCE,  AND  NOT  OF  A  MIXTURE. 

A.  Observe  its  smell,  taste,  and  action  upon  test-papers  (18). 

B.  Evaporate  a  little  on  a  slip  of  glass  (p.  20). 

(a)  If  no  residue  is  left,  and  the  liquid  is  destitute  of 

color,  smell,  taste,  and  action  on  test-papers,  it 
is  water  only. 

(b)  If  a  residue  is  left,  or  if  the  conclusion  is  doubtful, 

evaporate  a  larger  quantity  of  the  liquid  in  a 
porcelain  dish  (84),  and  if  there  is  any  residue, 

*  Sulphur  and  phosphorus  would  of  course  be  recognized  in  this 
experiment. 


182  UNKNOWN    LIQUIDS    EXAMINED. 

examine  it  as  directed  for  an  unknown  solid  sub- 
stance (237).  Carefully  observe  whether  any 
odor  is  evolved  during  the  evaporation. 

Whilst  the  evaporation  is  proceeding,   the  analyst  may 
examine  another  portion  of  the  solution  by  Tables  A  and  H. 

(c)  If  no  residue  is  left  on  evaporation,  and  the  liquid 
is  acid  to  test-papers,  examine  for 


Sulphuric  acid  (102) 
Hydrochloric  acid  (105) 
Nitric  acid  (109) 
Acetic  acid  (149) 
Sulphurous  acid  (100) 
Chloric  acid  (90) 
Formic  acid  (150) 
Lactic  acid  (232) 


Butyric  acid  (215) 
Hydriodic  acid  (93) 
Hydrofluoric  acid  (89) 
Hydrofluosilicic  acid  (64) 
Carbonic  acid  (95) 
Hydrocyanic  acid  (99) 
Hydrosulphuric  acid  (97) 
Valerianic  acid  (218) 


Oleic  acid  (233). 

(e?)  If  no  residue  is  left  on  evaporation,  and  the  liquid 
is  alkaline  to  test-papers,  examine  for 

Ammonia  (75)       |       Aniline  (219)       |       Nicotine  (214). 

(e)  If  no  residue  is  left  on  evaporation,  and  the  liquid  is 
neither  acid  nor  alkaline,  examine  especially  for 


Alcohol  (209) 

Methylic  alcohol  (211) 

Acetone  (212) 

Aldehyde  (213) 

Phenole  (carbolic  acid)  (217) 


Ether  (221) 
Chloroform  (222) 
Bitter  almond  oil  (223) 
Nitrobenzole  (224) 
Benzole  (225) 


Glycerine  (231). 

When  no  clue  can  be  obtained,  the  analyst  must  carefully 
go  through  every  step  of  the  analytical  processes,  commencing 
at  Table  A. 


FIRST    M.B.    EXAMINATION. 


183 


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184  FIRST    M.B.    EXAMINATION. 

I.  THE  SUBSTANCE  is  SOLID. 
A.  Heat  the  substance  in  a  small  tube. 

(a)  It  evolves  ammonia  freely,  without  blackening. 

Examine  especially  for — 

Urea  (182)  |  Oxalate  of  urea  (192)    |  Oxalate  of  ammonia. 

(6)  It  evolves  a  pungent  odor  resembling  sulphurous 
acid. 

Examine  for  Nitrate  of  Urea  (192). 

(c)  It  evolves  an  agreeable  odor. 

Examine  especially  for — 
Benzole  acid  (154)     |  Hippuric  acid  (156)    j  Acetate  of  lead  (149). 

(d)  It  evolves  an  odor  resembling  that  of  coal  tar. 

Examine  especially  for — 


Cinchonine  (170) 
Quinine  (168) 


Sulphate  of  cinchonine  (170) 
Sulphate  of  quinine  (168) 


(e)  It  blackens  and  evolves  an  odor  of  burnt  ivood  or 
sugar. 

Examine  especially  for — 


Tartaric  acid  (158) 
Bitartrate  of  potash  (158) 
Citric  acid  (159) 
Starch  (187) 
Cane-sugar  (179) 


Grape-sugar  (180) 
Malic  acid  (160) 
Meconic  acid  (151) 
Gallic  acid  (153) 
Tannic  acid  (152). 


(/)  It  blackens  and  evolves  a  disagreeable  odor  of 
singed  animal  matter. 

Examine  especially  for — 


Uric  acid  (161) 
Urate  of  soda  (161) 
Urate  of  ammonia  (161) 
Morphine  (165) 
Hydrochlorate    of    morphine 


(165) 


Acetate  of  morphine  (165) 
Meconate  of  morphine  (165) 
Strychnine  (167) 
Ferrocyanide  of  potassium  (113) 
Ferridcyanide  of  potassium  (p. 
84). 


(g)  It  evolves  vapors  which  provoke  violent  coughing. 
Examine  especially  for  Succinic  Acid  (155). 


FIRST    M.B.    EXAMINATION.  185 

(h)  It  evolves  cyanogen  (known  by  its  odor,  and  pink 

flame). 

Examine  especially  for  Cyanide  of  Mercury  (99). 
(i)  It  passes  off  in  vapor  without  any  of  the  above 
indications. 

Examine  especially  for — . 

Oxalate  acid  (115)  |      Oxalate  of  ammonia  (115). 

B.  Heat  the  substance  on  a  piece  of  broken  porcelain,  at 
first  with  the  ordinary  flame,  and  afterwards  ivith 
the  outer  blowpipe-flame, 
(a)  A  residue  is  left. 

Moisten  it  with  water,  and  test  with  red  litmus 

paper. 
If  it  be  decidedly  alkaline, 

Examine  for — 


Cyanide  of  potassium  (p.  84) 
Ferrocyanide  of  potassium  (113) 
Ferridcy  anide  of  potassium(p .  84) 
Sulphocyanide  of  potassium  (p. 

101) 
Bitartrate  of  potash  (158) 


Oxalate  of  potash  (115) 

lime  (115) 
Acetate  of  potash  (149) 

"  soda  (149) 

Urate  of  soda  (161) 
Tartar  emetic  (p.  49). 


If  the  residue  is  yellow  or  red, 
Examine  especially  for  Acetate  of  Lead  (149). 
(b)  No  residue  is  left.     Pass  on  to  C. 
C.  Heat  the  substance  with  water, 
(a)  It  does  not  dissolve  in  water. 

Add  Potash. 
If  it  dissolves  in  Potash, 

Examine  especially  for* — 


Benzoic  acid  (154) 
Hippurie  acid  (156) 
Uric  acid  (161) 
Gallic  acid  (153) 


Bitartrate  of  potasli  (158) 
Urate  of  soda  (161) 
Urate  of  ammonia  (161). 


*  It  is  not  safe  to  infer  the  absence  of  these  when  the  substance 
dissolves  in  water. 


18G  FIRST    M.B.    EXAMINATION. 

If  it  does  not  dissolve,  in  potash, 

Add  Hydrochloric  Acid.* 
It  dissolves. 


Examine  especially  for — 


Morphine  (165) 
Quinine  (168) 
Cinchonine  (170) 
Strychnine  (167) 


Sulphate  of  quinine  (168) 

"  cinchonine  (170) 

Oxalate  of  lime  (58). 


(6)  It  dissolves  in -water. 

Test  the  solution  with  blue  and  red  litmus  paper, 

and,  cautiously,  by  tasting. 
I.    The  solution  is  decidedly  acid,  but  not  astringent. 

Examine  especially  for — 

Tartaric  acid  (158)  Malic  acid  (160) 

Oxalic. acid  (115)  Meconic  acid  (151) 

Citric  acid  (159)  Hippuric  acid  (156) 

Succinic  aci'd  (155)  Bitartrate  of  potash  (158). 

II.    The  solution  is  acid  and  astringent. 
Examine  especially  for  Gallic  (153)  and  Tannic  Acids  (152). 

in.    TJie  solution  is  alkaline. 
Examine  especially  for  Cyanide  of  Potassium  (99). 

iv.    The  solution  has  a  sweet  taste. 

Examine  especially  for — 

Cane-sugar  (179)        |  Grape-sugar  (180)     |  Acetate  of  lead  (149). 
v.    The  solution  is  bitter ;  pass  on  to  D. 
vi.    The  solution  has  a  yellow  or  green  color. 

Examine  especially  for — 
Ferrocyanide  and  Ferridcyanide  of  potassium  (p.  80). 

*  A  blue  substance,  becoming  brown  with  potash,  and  again  blue 
with  hydrochloric  acid,  is  probably  Prussian  blue.  To  confirm,  boil 
with  potash,  filter,  and  test  the  solution  with  excess  of  acetic  acid, 
and  perchloride  of  iron.  Abundant  blue  precipitate  indicates 
Prussian  blue. 


FIRST    M.B.    EXAMINATION.  187 

vii.    The  solution  is  not  decidedly  acid  or  alkaline,  and 
has  no  characteristic  taste  or  color. 

Examine  especially  for — 


Oxalate  of  ammonia  (115) 
potash  (115) 

Acetate  of  potash  (149) 
soda  (149) 


Cyanide  of  mercury  (31) 
Sulphocyanide  of  potassium 

(p.  101) 
Urea  (182). 


D.  Dissolve  a  little  of  the  substance  in  water,  or  in  a  little 
dilute  hydrochloric  acid,  and  test  with  a  solution  of 
iodine  in  iodide  of  potassium. 

If  a  brown  precipitate  is  obtained, 

Examine  for  an  alkaloid  by  Table  O. 

If  a  yellow  precipitate  is  produced,  examine  for  acetate  of 
lead  (p.  29). 

If  a  blue  precipitate  is  produced,  examine  for  starch  (187). 

If  the  iodine  solution  is  bleached,  examine  for  a  cyanide 
(99). 

Should  no  clue  have  been  hitherto  obtained,  examine  the 
substance  for  an  organic  acid  by  Table  K.  and  for  an  organic 
alkaloid  by  Table  O ;  and,  as  a  last  resource,  for  a  metal  by 
Table  A,  and  for  an  inorganic  acid  by  Table  G,  in  the  hope 
that  some  light  may  thus  be  thrown  upon  the  nature  of  the 
substance. 

II.  THE  SUBSTANCE  is  A  LIQUID. 

A.  Ascertain  whether  it  has  the  odor  of 

Acetic  acid  (149)       |    Hydrocyanic  acid  (99)      |    Alcohol  (209). 

B.  Evaporate  a  little  in  a  porcelain  dish,  taking  care  not  to 

continue  the  heat  after  the  dish  is  dry,  and  observing 
any  odor  during  evaporation. 

(a)  If  no  residue  is  left,  examine  for 

Acetic  acid  (149)  1  Alcohol  (209) 

Hydrocyanic  acid  (99)  Glycerine  (231). 

(b)  If  a  residue  is  left,  examine  the  action  of  heat  upon 

it,  drawing  inferences  according  to  pp.  184,  18o. 


188  FIRST    M.B.    EXAMINATION. 

C.    Test  a  small  portion  of  the  solution  with  a  solution  of 
iodine  in  iodide  of  potassium. 

If  a  brown  precipitate  is  obtained,  examine  another  part 
of  the  solution  for — 


Morphine  (165) 
Hydrochlorate  of  morphine 

(165) 
Acetate  of  morphine  (165) 


Meconate  of  morphine  (165) 
Quinine  (168) 
Cinchonine  (170) 
Strychnine  (167). 


Yellow  precipitate,  examine  for  acetate  of  lead  (p.  29). 
Blue  precipitate,  examine  for  starch  (187). 
If  the  iodine  solution  is  bleached,  examine  for  a  cyanide 
(99). 

D.    Test  the  liquid  with  blue  and  red  litmus  papers. 

(a)  The  liquid  is  acid. 

Add,  to  a  small  portion,  potash,  till  it  is  very 
slightly  alkaline,  and  stir  with  a  glass  rod. 

If  a  precipitate  is  produced,  add  acetic  acid  in 
excess;  should  this  fail  to  redissolve  it,  exa- 
mine for  Oxalate  of  Lime  (58). 

If  acetic  acid  dissolves  the  precipitate,  examine 
for— 

Acetate  of  lead  (149)  I  Quinine  (168) 

Morphine  (165)  Cinchonine  (170) 

Strychnine  (167). 

(b)  The  liquid  is  alkaline. 

Add,  to  a  small  portion,  acetic  acid,  till  it  is 

slightly  acid,  and  stir  with  a  glass  rod. 
If  a  precipitate  is  obtained,  examine  for — 

Benzoic  acid  (154)  I  Uric  acid  (161) 

Hippuric  acid  (156)  Tartaric  acid  (158).   . 

And  for  the  potash,  soda,  or  ammonia  holding  them  in  solution  (72). 

If  no  precipitate  is  obtained,  add  to  another 
portion  hydrochloric  acid  (cone.)  in  slight 
excess,  and  stir  with  a  glass  rod. 


FIRST    M.B.    EXAMINATION.  189 

Benzoic  and  hippuric  acids  would  now  be  precipitated, 
though  they  might  have  escaped  precipitation  by  acetic  acid. 

If  no  clue  has  yet  been  obtained,  examine  the  substance 
for  an  organic  acid  by  Table  K,  and  for  an  organic  alkaloid 
by  Table  O;  and,  as  a  last  resource,  for  a  metal  by  Table  A, 
and  for  an  inorganic  acid  by  Table  G,  in  the  hope  that  some 
light  may  thus  be  thrown  upon  the  nature  of  the  substance. 


190 


ANALYSIS    BY    THE    BLOWPIPE.       TABLE    R. 


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REDUCTION  ON  CHARCOAL. 


191 


EXPLANATIONS  AND  INSTRUCTIONS  ON 
TABLE  R. 

241.  To  reduce  metals  on  charcoal  before  the  blowpipe — 
Select  a  piece  of  hard  thoroughly  carbonized  charcoal,  free 
from  crevices,  not  less  than  four  inches  long  and  one  or  two 
inches  in  diameter ;  grind  down  one  of  its  sides  to  a  flat 
surface  (fig.  73)  on  the  hearthstone.  Scoop  a  very  shallow 

Fio.  73. 


Fi«.   74. 


cavity  at  a  with  the  blade  of  a  knife,  making  it  smooth  and 
round.  Place  in  this  a  grain  or  two  of  the  substance  to  be 
examined,  previously  reduced 
to  powder  (124),  and  cover  it 
with  dry  powdered  carbonate 
of  soda.  Hold  the  charcoal 
and  the  blowpipe  in  the  posi- 
tions represented  in  fig.  74. 
Direct  the  point  of  the  inner 
(reducing)  flame  upon  the  spe- 
cimen in  the  cavity,  blowing 
gently  at  first  lest  the  powder 

should  be  scattered,  and  allow  the  outer  (oxidizing  flame)  to 
play  over  the  flat  surface  of  the  charcoal. 

Observe  very  closely  the  appearances  presented  by  the 
mass  under  the  influence  of  heat,  especially  noticing  whether 
any  minute  metallic  globules  are  to  be  seen  in  the  fused 


tluction  on  charcoal. 


102          ,  INCRUSTATION.       LEVIGATION. 

substance.     If  this  be  the  case,  try  to  fuse  them  together 
into  larger  globules. 

Should  an  infusible  mass  be  left  after  the  first  application 
of  the  blowpipe-flame,  add  more  carbonate  of  soda,  and  again 
heat  intensely,  since  the  binoxide  of  tin  often  requires  re- 
peated additions  of  carbonate  of  soda  to  bring  it  into  fusion 
and  reduce  it  to  the  metallic  state. 

Watch  the  appearance  of  the  mass  after  withdrawing  it 
from  the  flame,  noting  any  changes  of  color  which  may 
occur  in  cooling. 

The  surface  of  the  charcoal  is  generally  covered,  for  some 
distance  beyond  the  cavity,  with  a  deposit  or  incrustation 
which  sometimes  consists  of  a  thin  white  film  of  ash  left  after 
the  charcoal  has  burnt  away,  and  sometimes  of  a  more 
opaque  coating  of  some  metallic  oxide  formed  by  the  com- 
bustion of  metallic  vapor  in  passing  through  the  outer  flame. 

Observe  very  carefully  the  color  and  general  appearance 
of  this  incrustation,  comparing  the  results  with  Table  S. 

If  any  globule  of  metal  is  visible,  detach  it  carefully  from 
the  fused  mass  with  the  point  of  a  knife,  place  it  upon  a  hard 
surface,  such  as  a  porcelain  slab  or  the  bottom  of  an  inverted 
mortar,  and  press  it  with  a  knife-blade,  to  ascertain  whether 
it  is  malleable  or  brittle.  Compare  the  results  with  Table  S. 

When  no  metallic  globule  is  visible,  or  when  the  metallic 
globule  has  been  removed,  scrape  the  mass,  together  with  the 
particles  of  charcoal  in  contact  with 
FlG- 75-  it,  into  a  small  agate  mortar  (fig.  75), 

moisten  it  with  one  or  two  drops  of 
water,  and  grind  it  into  a  paste.    Stir 
this  paste  up  with  more  water,  then 
Agate  mortar.  fill  the  mortar  with  water,  allow  it  to 

rest  for  a  few  seconds,  in  order  that 

any  metallic  particles  may  subside,  and  carefully  pour  off  the 
water,  carrying  with  it  the  lighter  particles"  of  charcoal  and 


LEVIGATION.       BROWN    SLAG.  193 

slag  (fig.  76).  Repeat  this  grinding  and  levigation  until 
metallic  particles  are  distinctly  visible  at  the  bottom  of  the 
mortar,  or  until  the  whole  has  been  washed  away  without 
showing  any  metal. 

FIG.  76. 


Levigatiou  in  blowpipe  analysis. 

The  metals  which  are  generally  detected  in  this  way, 
are — 

Copper,  which  gives  characteristic  red  spangles. 

Tin,  in  white  silvery  spangles  of  considerable  size. 

Iron,  in  gray  metallic  powder,  attracted  by  the  magnet. 

242.  Fused  carbonate  of  soda  is  absorbed  into  the  pores 
of  the  charcoal,  but  very  frequently  a  slag  is  formed  which 
refuses  to  sink  into  the  charcoal,  and  remains  on  the  surface.* 
This  is  the  case  with  silicate  and  borate  of  soda,  formed  when 
silicic  and  boracic  acids  are  present.  Sulphide  of  sodium 
also  generally  remains  on  the  surface  of  the  charcoal  as  a 
brown  mass,  the  formation  of  which  renders  it  highly  probable 
that  the  substance  under  examination  is  a  sulphide. 

Although  most  metallic  oxides  would  be  reduced  to  the 
metallic  state  by  the  combined  action  of  the  blowpipe-flame 
and  the  charcoal  support,  it  is  necessary  to  add  carbonate  of 
soda  for  the  following  reasons  : — 

(1)  The  carbonate  of  soda  removes  any  acid  (silicic  acid, 

*  Cyanide  of  potassium  will  occasionally  assist  in  getting  rid  of 
such  slags. 
17 


194  BLOWPIPE    ANALYSIS.       BORAX-BEADS. 

for  example)  or  non-metallic  element  (such  as  sulphur)  which 
would  hinder  the  separation  of  the  metal. 

(2)  By  thus  forming  a  slag  through  which  the  metal  may 
sink,  the  re-oxidation,  and  in  some  cases  the  volatilization, 
of  the  metal,  are  in  great  measure  prevented. 

(3)  Carbonate  of  soda,  strongly  heated  with  charcoal,  yields 
vapor  of  sodium,  which  acts  as  a  powerful  reducing  agent 
upon  metallic  compounds. 

242«.  When  the  substance  is  heated  by  itself  on  char- 
coal it  may  furnish  any  of  the  results  indicated  in  Table  S, 
and,  in  addition,  other  information  may  often  be  ob- 
tained more  easily  than  when  carbonate  of  soda  has  been 
added. 

(1)  The  substance  passes  away  entirely  in  the  form  of 
vapor.     Probably  mercury,  arsenic,  or  ammonium  is  present. 
See  Table  II,  col.  5. 

(2)  An  infusible  mass  remains  upon  the  charcoal.    Proba- 
bly aluminium,  zinc,  or  magnesium  is  present.     See  Table 
R,  col.  4. 

(3)  A  sparkling  combustion  of  the  charcoal  takes  place. 
Probably  a  nitrate  or  a  chlorate  is  present.     See  Table  W. 

(4)  A  smell  of  burning  sulphur  is  perceived.     Probably 
sulphur  or  a  sulphide  or  sulphate  -is  present.     See  Tables  X 
and  Z. 

243.  To  detect  metals  by  the  colors  which  they  impart  to 
a  bead  of  borax-glass — Take  a  piece  of  platinum  wire,  of 

such  a  thickness 

FlG-  77-  that  three  inches 
<?HS^Sj!                          St   weigh  one  grain, 

Platinum  for  borax-beads.  and   Seal    it   into 

a  glass  handle  as 

described  at  p.  78.  Bend  the  end  of  it  round  into  a  small 
loop  (fig.  77),  which  must  not  be  larger  than  the  transverse 
section  of  the  blowpipe-flame. 


BLOWPIPE    ANALYSIS.       COLORED    FLAME    TEST.       195 


Make  this  loop  red  hot, 
and  dip  it  into  powdered 
borax,  of  which  a  consider- 
able quantity  will  stick  to 
the  wire.  Fuse  this  in  the 
blowpipe-flame  (fig.  78)  to 
a  bead  which  should  be  per- 
fectly colorless  and  trans- 
parent even  after  cooling. 


FIG. 78. 


Borax-bead  test. 


Place  one    or    two    small 

particles  of  the  substance  under  examination  upon  a  piece  of 
paper  close  at  hand,  heat  the  borax-bead,  and  touch  one  of 
the  particles  with  it  so  that  it  may  stick  to  the  bead. 

Fuse  the  bead  at  the  extreme  point  of  the  outer  (oxidiz- 
ing) flame  of  the  blowpipe,  until  the  substance  appears  to 
have  been  dissolved  by  the  borax,  and  observe  the  color  of 
the  bea-d  while  hot  and  after  cooling.  Should  the  bead  be 
opaque,  too  large  a  quantity  of  the  substance  has  been  added, 
and  the  experiment  must  be  repeated. 

If  the  bead  remains  colorless,  another  particle  of  the  sub- 
stance must  be  fused  with  it,  and  so  on,  until  a  reasonable 
proportion  has  been  added  without  producing  any  result. 

The  bead  is  afterwards  exposed  to  the  point  of  the  inner 
(reducing)  flame  of  the  blowpipe,  and  the  color  of  the  glass 
carefully  observed. 

The  results  are  compared  with  Table  T. 

To  clean  the  wire  for  a  new  test,  dip  the  red-hot  bead  into 
water,  when  it  will  become  brittle  and  may  be  easily  detached 
from  the  loop,  which  is  then  opened  and  the  wire  scraped 
clean  with  the  thumb-na  !. 

244.  To  detect  metals  by  the  color  which  they  impart  to 
the  blow  pipe-flame. — Take  a  straight  piece  of  platinum  wire,  as 


196       BLOWPIPE    ANALYSIS.       COLORED    FLAME    TEST. 

recommended  at  p.  78,  dip  it  in  hydrochloric  acid,*  and  expose 
it  repeatedly  to  the  point  of  the  inner  (reducing)  blowpipe- 
flame  till  it  no  longer  imparts  a  distinct  color  to  the  outer 
flame.  Again  moisten  it  with  hydrochloric  acid,  take  upon 
it  a  minute  quantity  of  the  substance  under  examination, 
and  again  expose  it  to  the  point  of  the  inner  flame  (fig.  79). 

FIG. 79. 


Compare  the  results  with  Table  U. 

Some  metals  (barium,  for  example)  so  fuse  into  the  plati- 
num that  it  is  scarcely  possible  to  get  rid  of  them  in  order 
to  prepare  the  wire  for  a  fresh  test.  When  this  is  found  to 
be  the  case,  the  extremity  of  the  wire  must  be  cut  off. 

245.  To  detect  metals  by  the  cobalt  test  before  the  blow- 
pipe.— The  solution  of  nitrate  of  cobalt  should  contain  about 
one  part  of  the  salt  dissolved  in  ten  parts  of  water,  and  is 
conveniently  kept  in  a  bottle  provided  with  a  perforated  cork 
carrying  a  piece  of  glass  tube  long  enough  to  reach  to  the 
bottom  of  the  bottle  and  to  project  an  inch  or  two  above  the 
cork  (fig.  80).  This  tube  should  be  partly  closed  at  each 
end  by  directing  the  blowpipe-flame  upon  it.  When  the  upper 
orifice  of  this  tube  is  closed  with  the  finger  (fig.  81),  and  the 
tube  withdrawn  from  the  bottle,  the  cobalt  solution  is  retained 

*  This  wire  should  not  be  dipped  into  the  bottle  of  hydrochloric 
acid,  but  into  a  small  quantity  of  the  acid  in  a  small  glass  or  por- 
celain capsule. 


BLOWPIPE    ANALYSIS. 


197 


FIG.  80. 


FIG.  81. 


FIG.  82. 


in  it  by  atmospheric  pressure,  and  may  be  suffered  to  fall,  drop 
by  drop,  upon  the  mass  under  examination.  One  or  two 
drops  will  generally  suffice.  An  intense  heat  should  then  be 
applied  for  several  seconds,  the  result  being  compared  with 
column  4  of  Table  R,  p.  190. 
246.  To  detect  mercury, 
arsenic,  and  ammonia  by  the 
blowpipe — Dry  the  carbon- 
ate of  soda  by  heating  it 
moderately  on  a  piece  of  glass 
or  tin-plate,  or  on  the  blade 
of  a  spatula.  Allow  it  to  cool, 
and  mix  it  with  the  powdered 
substance  under  examination, 
upon  a  piece  of  paper,  using 
at  least  six  times  as  much 
carbonate  of  soda  as  of  the 
substance.  Scrape  enough 
powder  off  a  piece  of  charcoal 

to  impart  a  dark-gray  color  to  the  mixture.  Introduce  the 
mixture  into  a  small  dry  German  glass  tube  (p.  33),  cleanse 
the  upper  part  of  the  tube  from  adhering  particles  of  sub- 
stance with  a  match  stick  or  a  roll  of  paper,  and  rap  the  tube 
against  the  table  so  as  to  shake  the  powder  into  the  position 


198  BLOWPIPE    ANALYSIS. 

shown  in  fig.  82,  leaving  a  clear  passage  for  the  vapor.  Hold 
the  tube  in  a  narrow  band  of  folded  paper,*  and  heat  it  in 
the  non-luminous  part  of  the  flame  (fig.  83)  so  as  not  to  smoke 
it.  If  none  of  the  results  mentioned  in  column  5  of  Table 
R  (page  190)  are  observed,  direct  the  blowpipe-flame  upon 
the  bottom  of  the  tube  until  the  glass  begins  to  fuse. 

Beginners  frequently  fail  in  this  test,  in  consequence  of 
their  allowing  condensed  water  to  trickle  back  upon  the  hot 
mixture,  causing  it  to  spirt  up  and  soil  the  sides  of  the  tube. 

NOTES  TO  TABLE  R. 

247.  Great  care  is  necessary  to  avoid  error  in  applying 
the  blowpipe  test  for  aluminium. 

The  solution  of  nitrate  of  cobalt  itself  leaves  a  blue  mass 
of  the  anhydrous  nitrate  when  evaporated  to  dryness  by  the 
heat  of  the  flame  ;  but  when  this  blue  mass  is  strongly  heated, 
it  is  converted  into  the  black  oxide  of  cobalt,  whereas  the 
blue  mass  furnished  by  the  combination  of  alumina  with 
oxide  of  cobalt  (aluminate  of  cobalt)  becomes  of  a  brighter 
blue  color  when  more  intensely  heated. 

The  alkaline  phosphates  and  borates  also  give  a  blue  mass 
with  nitrate  of  cobalt,  but  this  mass  assumes  the  condition  of 
a  fused  glass,  whilst  the  alumina  blue  is  perfectly  infusible. 

To  ascertain  what  compound  of  aluminium  is  under  exami- 
nation, the  analyst  should  refer  to  p.  59. 

248.  The  presence  of  zinc  should  be  confirmed  by  ob- 
serving that  the  infusible  mass,  before  the  addition  of  nitrate 
of  cobalt,  is  yellow  while  hot,  and  becomes  white  on  cooling. 

To  ascertain  what  compound  of  zinc  is  under  examination, 
the  analyst  should  refer  to  p.  61. 

*  If  any  moisture  is  seen  to  condense  on  the  sides  of  the  tube, 
hold  the  latter  with  its  mouth  somewhat  inclined  downwards,  lest 
the  drops  should  run  back  and  crack  the  glass. 


BLOWPIPE    ANALYSIS.  199 

249.  The  pink  color  of  the  compound  formed  by  mag- 
nesia with  oxide  of  cobalt  is  very  pale,  and  might  be  over- 
looked in  a  cursory  inspection,  especially  if  the  observer  be 
dazzled  by  the  incandescence  of  the  ignited  mass. 

To  ascertain  what  compound  of  magnesium  is  under  ex- 
amination, the  analyst  should  refer  to  p.  23. 

250.  The  globules  of  mercury  composing  this  sublimate 
are  sometimes  so  minute  that  it  has  the  appearance  of  a  gray 
coating  upon  the  tube ;  on  rubbing  it  with  a  lucifer- match 
stick,  the  particles  unite  into  distinct  globules. 

To  ascertain  what  compound  of  mercury  is  under  exami- 
nation, the  analyst  should  refer  to  pp.  27  and  40. 

251.  If  arsenic  be  present,  a  garlic  odor  will  generally 
be  perceptible  at  the  mouth  of  the  tube,  and  should  have  been 
already  noticed  in  column  1. 

A  black  shining  ring  is  sometimes  formed  upon  the  sides 
of  the  tube,  in  cases  where  no  arsenic  is  present,  in  conse- 
quence of  the  deposition  of  a  coating  of  lustrous  carbon  from 
the  action  of  heat  upon  tarry  matters,  distilled,  either  from 
imperfectly  prepared  charcoal,  or  from  organic  matter  in  the 
substance  analyzed. 

Sulphide  of  mercury  may  also  furnish  a  black  ring  if  the 
quantity  of  carbonate  of  soda  employed  in  the  experiment  is 
insufficient  to  remove  the  whole  of  the  sulphur. 

To  ascertain  that  the  ring  does  really  consist  of  arsenic, 
make  a  deep  file-mark  on  each  side  of  it,  and  break  off  the 
glass  with  a  jerk.  Wrap  the  piece  of  glass  containing  the 
ring  in  a  piece  of  stout  paper,  and  break  it,  with  a  few  blows, 
into  fragments,  but  not  into  powder.  Select  those  fragments 
which  appear  to  be  well-coated,  place  them  in  a  small  tube 
sealed  at  one  end,  and  heat  them  gently  above  the  point  of 
an  ordinary  flame  as  shown  in  fig.  84.  The  arsenic  will  be 
slowly  converted  into  vapor,  combining  with  the  oxygen  of 


200 


BLOWPIPE    TEST    FOR    ARSENIC. 


the  air  in  the  tube  to  form  arsenious  acid,  which  will  be  de- 
posited in  small  brilliant  crystals  upon  the  cooler  part  of  the 
tube.  Under  the  microscope,  the  octahedral  shape  of  these 
crystals  will  be  distinctly  seen  (fig.  85). 


Fro.  84. 


FIG.  85. 


If  there  be  more  arsenic  than  can  be  oxidized  by  the  air 
in  the  tube,  a  dark  ring  of  arsenic  will  accompany  the  crys- 
tals, and  may  be  oxidized  by  a  second  sublimation. 

The  smallest  fragment  of  arsenious  acid  may  be  identified 
with  perfect  certainty  in  the  following  manner : 

Draw  out  a  piece  of  narrow  German  tube  to  a  long  point 
(17),  and  seal  it  in  the  blowpipe-flarne.  Drop  into  this  point 

the  fragment  supposed  to  be 
FIG.  86.  arsenious  acid.    Place  three 

or  four  little  pieces  of  char- 
coal in  the  wider  part  of 
the  tube  (fig.  86),  and  heat 
them  to  redness  in  the 
blowpipe-flame.  Then  heat 
quickly  the  point  of  the 
tube  so  as  to  drive  the 

vapor  of  arsenious  acid  over  the  red-hot  charcoal,  which  will 
remove  the  oxygen  of  the  arsenious  acid,  and  a  shining  black 
ring  of  arsenic  will  be  deposited  upon  the  cooler  part  of  the 
tube. 

To  ascertain  what  compound  of  arsenic  is  under  examina- 
tion, the  analyst  should  refer  to  (35). 


BLOWPIPE    TEST    FOR    ANTIMONY. 


201 


252.  An  odor  of  ammonia  might  also  arise  in  this  ex- 
periment, from  the  decomposition  by  heat  of  organic  matters 
containing  nitrogen ;  but  such  substances  would  be  car- 
bonized or  blackened  when  heated  in  a  small  tube  by  them- 
selves, and  would  evolve  vapors  having  the  offensive  smell 
of  singed  hair,  and  restoring  the  blue  color  to  red  litmus 
paper. 

To  ascertain  what  compound  of  ammonium  is  under  exa- 
mination, the  analyst  should  refer  to  (75). 


TABLE  S. 
253.  Metals  reduced  on  Charcoal. 


Metallic  Globules. 

Incrustations. 

Remarks. 

Antimony 

Very  brittle  

White    5 

Metal  volatilizes 

White 

(254,  255). 
Garlic  fumes  (256) 

Bismuth,  . 

Brittle  

Yellow  j 

Metal  very  fusible 

Copper  .  .  . 
Lead  

Red,  malleable  .. 
Soft,  malleable.. 

Little  or  none.  < 
Yellow  s 

(257). 
Difficult  to  fuse 
(258,  259,  260). 
Metal  marks  paper 

Silver  .... 

Malleable  

Little  or  none   < 

(261,  262,  263). 
Not  oxidizable 

Tin  

Malleable  

Little  or  none   < 

(264,  265). 
Easily  oxidizable, 

Zinc  

None  j 

Yellow,  hot  ;    "i 
white  when 
cold   ) 

very  fusible  (266). 

Infusible   mass 
emitting  a  greenish- 
white  light  (267) 

V. 

NOTES  TO  TABLE  S. 

254.  Antimony  is  generally  reduced  by  the  blowpipe  in 
minute  globules,   which  are  not  easily  united   into  a  large 


202  BLOWPIPE    TEST    FOR    BISMUTH. 

globule.  It  is  easier  to  obtain  a  large  globule  of  antimony  if 
cyanide  or  ferrocyanide  of  potassium  is  employed  instead  of 
carbonate  of  soda. 

Antimony  generally  gives  off  a  white  smoke,  and  covers 
the  charcoal  with  an  incrustation  even  beyond  the  limits 
of  the  oxidizing  flame.  The  incrustation  generally  appears 
bluish-white,  the  black  charcoal  being  seen  through  it. 

The  globule  of  antimony  is  extremely  brittle,  falling  to  a 
metallic  powder  when  struck  or  pressed.  The  metallic  ap- 
pearance of  the  powder  must  be  observed,  or  else  brittle  glo- 
bules of  slag  may  be  mistaken  for  antimony. 

255.  The  compounds  of  antimony  most  likely  to  be  met 
with  in  blowpipe  analysis,  are — 

Sulphide  of  antimony,      Tartar  emetic,      Oxide  of  antimony. 

These  substances  have  been  described  at  (39). 

To  that  description  it  may  here  be  added,  that — 

Sulphide  of  Antimony  gives  a  brown  mass  when  fused 
with  carbonate  of  soda  on  charcoal  (242). 

Tartar  emetic  crackles  (decrepitates)  and  sparkles  (scin- 
tillates) when  heated  alone  on  charcoal,  at  the  same  time 
giving  the  violet  flame  of  potassium. 

256.  The  presence  of  arsenic  should  be  confirmed  as  in 
column  5,  Table  R. 

When  arsenic  has  been  discovered,  (35)  should  be  referred 
to,  in  order  to  ascertain  whether  the  substance  under  exami- 
nation is  one  of  those  described  there.  If  it  is  not  then 
identified,  the  blowpipe  examination  must  be  continued,  with 
the  view  of  discovering  another  metal,  since  arsenic  is  often 
present  in  considerable  quantity  in  ores  of  which  it  does  not 
form  the  most  important  ingredient. 

257.  Bismuth  is  often  mistaken  for  lead  by  beginners, 
because  a  globule  of  this  metal  is  flattened  when  struck  or 
pressed,  as  if  it  were  malleable  ;  but  if  the  flattened  bead  be 
touched  with  the  point  of  the  knife,  it  will  be  found  to  break 
to  pieces,  which  is  never  the  case  with  lead. 

Should  any  doubt  exist  as  to  the  presence  of  bismuth, 


BLOWPIPE    ANALYSIS.       ROASTING.  203 

heat  a  portion  of  the  substance,  on  charcoal,  with  a  mixture 
of  equal  parts  of  sulphur  and  potassium  iodide,  when  bis- 
muth will  give  a  bright  red  incrustation  on  the  cooler  part 
of  the  charcoal. 

The  compounds  of  bismuth  which  are  most  frequently  met 
with,  are  described  at  (29). 

258.  Although  compounds  of  copper  are  easily  reduced  to 
the  metallic  state  before  the  blowpipe,  a  beginner  generally 
experiences  some  difficulty  in  obtaining  a  globule  of  mal- 
leable copper.     The  metal  first  presents  itself  as  a  red-brown 
mass,  apparently  infusible  ;  but  if  this  be  exposed  to  the  point 
of  the  blue  inner  flame,  which  is  the  hottest  region  orjjocus 
of  the  blowpipe-flame,  it  fuses  into  a  metallic  globule  of  tough 
copper  which  requires  a  sharp  blow  to  flatten  it. 

This  experiment  affords  an  excellent  lesson  in  finding  the 
focus  of  the  flame. 

259.  Copper  compounds  containing    sulphur  or  arsenic 
yield  a  brittle  globule  when  reduced  ;    to  avoid  this,  such 
compounds  must  be  well  roasted  before  adding  carbonate  of 
soda,  by  exposing  them,  on  charcoal,  to  the  point  of  the  outer 
(oxidizing)  flame  so  long  as  th'ey  exhale  any  odor  of  sul- 
phurous acid,  or  any  garlic  odor  indicating  arsenic. 

260-    The  distinctive  characters  of  the  principal  com- 
pounds of  copper  have  been  mentioned  at  (27). 

Beside  these,  the  blowpipe  analyst  is  likely  to  meet  with 

Copper  pyrites,  composed  of  copper,  iron,  sulphur. 

Gray  copper  ore,       '  <        {      ^ulpku™'  antim°ny  '  ai'SenlC'  and 


Copper  Pyrites,  Cu2S.Fe2S3,  may  generally  be  recognized 
by  its  yellow  color  and  metallic  lustre  ;  some  of  its  varieties 
{peacock  ore)  exhibit  beautiful  rainbow  tints.  The  presence 
of  iron  may  be  proved  either  by  extracting  the  magnetic 
particles  from  the  slag  and  surrounding  charcoal  by  leviga- 
tion,  as  directed  in  (2-il),  or  by  fusing  a  particle  of  the  ore 
with  a  bead  of  borax  (243),.  in  a  very  hot  reducing  (inner) 


204  BLOWPIPE  TEST  FOR  LEAD. 

flame,  when  the  ferrous  oxide  will  impart  a  bottle-green 
color  to  the  glass,  if  the  temperature  be  sufficiently  high  to 
fuse  the  copper  into  a  minute  globule  which  separates  from 
the  borax. 

Gray  Copper  Ore  has  a  steel-gray  color  and  metallic  lustre. 

If  it  be  heated  alone  on  charcoal  before  the  blowpipe,  the 
sulphur  and  arsenic  may  be  recognized  by  their  characteristic 
odors,  and  the  antimony  by  its  white  incrustation. 

To  obtain  a  bead  of  malleable  copper  from  gray  copper 
ore,  it  must  be  well  roasted  (in  powder)  in  the  outer  flame 
until  no  more  smell  of  sulphur  or  arsenic  is  perceptible,  then 
reduced  in  the  inner  flame,  with  addition  of  carbonate  of 
soda,  and  the  metallic  globule  exposed  to  an  intense  and  pro- 
longed heat  at  the  point  of  the  inner  flame  to  volatilize  the 
antimony. 

Brass  (Copper  and  Zinc)  is  recognized  by  its  giving  the 
incrustation  of  oxide  of  zinc,  which  is  yellow  when  hot,  and 
becomes  white  as  it  cools.  All  the  zinc  may  be  expelled  by 
protracted  heating  in  the  point  of  the  inner  flame,  and  mal- 
leable copper  will  be  left. 

Gun-metal  (Copper  and  Tin)  yields  a  globule  which  has 
externally  the  color  of  copper,  but  it  is  very  much  harder. 
By  judicious  exposure  to  the  outer  flame  the  bulk  of  the  tin 
may  be  oxidized  ;  and  if  a  little  more  carbonate  of  soda  be 
then  added,  and  the  reducing  flame  applied,  a  globule  of 
nearly  pure  copper  may  be  obtained. 

261.  Lead  is  very  easily  recognized  in  this  experiment 
by  the  facility  with  which  a  globule  of  metal  of  considerable 
size  may  be  obtained,  and  by  the  softness  of  the  globule, 
which  admits  of  being  flattened  out  and  cut  with  a  knife.    If 
the  flattened  globule  be  taken  between  the  finger-nails,  or 
upon  the  point  of  a  knife,  and  drawn  across  a  piece  of  paper, 
it  leaves  a  pencil-mark. 

262.  The  principal  compounds  of  lead  may  be  identified 
by  the  characters  described  at  (14). 

Galena  (sulphide  of  lead),  the  principal  ore  of  lead,  when 


CUPELLAT1ON  ON  CHARCOAL.  205 

fused  on  charcoal  with  carbonate  of  soda,  gives  a  brown  slag 
containing  sulphide  of  sodium,  and  if  an  insufficient  quantity 
of  carbonate  of  soda  be  employed,  the  globule  of  lead  is  often 
somewhat  brittle  from  the  presence  of  sulphur.  This  may 
be  avoided  by  roasting  the  powdered  galena  in  the  outer 
flame  as  long  as  it  smells  of  sulphur,  before  adding  the 
carbonate  of  soda.  Cyanide  or  ferrocyanide  of  potassium 
will  furnish  malleable  lead  with  galena,  without  previous 
roasting. 

Type-metal  and  shrapnel  bullets  are  composed  of  lead 
alloyed  with  one-fourth  of  antimony,  which  renders  the 
alloy  hard  and  brittle.  By  exposing  it  for  some  time  to 
the  point  of  the  reducing  (inner)  flame,  all  the  antimony 
may  be  expelled  in  vapor,  and  soft  malleable  lead  ob- 
tained. 

Pewter  and  Solder,  alloys  of  Lead  and  Tin,  are  recognized 
by  their  yielding  a  white  infusible  dross  of  binoxide  of  tin 
when  heated  in  the  outer  blowpipe-flame. 

263.  Detection  of  Silver  in  Lead  by  the  Blowpipe.  Cu- 
pellation. — Scoop  a  bowl-shaped  cavity  about  half  an  inch  in 
diameter,  in  a  piece  of  charcoal.  Fill  this  with  finely 
powdered  bone-ash,  which  must  be  pressed  down  with  the 
finger  so  as  to  fill  the  cavity  with  a  compact  mass  of  bone- 
ash,  smooth  and  slightly  hollowed  on  the  surface.  Place 
upon  this  a  small  piece  of  the  lead  under  examination,  hold 
the  charcoal  quite  horizontally, 
and  direct  the  extreme  point 
of  the  outer  (oxidizing)  flame 
upon  the  metal  (fig.  87).  The 
lead  immediately  fuses,  and 
the  oxide  which  is  formed  is 
absorbed,  in  the  liquid  state, 
by  the  porous  mass  of  bone- 
ash,  leaving  the  surface  of  the 
globule  covered  with  a  very 
thin  film  of  oxide  which  ex- 
18 


206  CUPELLATION  ON  CHARCOAL. 

hibits  rainbow  tints.  When  this  play  of  color  on  the  sur- 
face of  the  metal  ceases,  and  the  globule  is  no  longer  dimin- 
ished in  size,  it  consists  of  pure  silver,  which  is  often  no 
more  than  a  mere  speck,  though  easily  recognized  by  its 
brilliant  whiteness. 

It  is  sometimes  necessary  to  remove  the  lead  from  dross 
which  has  collected  round  it,  and  to  transfer  it  to  a  fresh 
cupel,  or  bed  of  bone-ash. 

When  the  lead  contains  copper,  the  surface  of  the  bone- 
ash  exhibits,  after  cooling,  a  green  stain,  whilst  pure  lead 
imparts  a  yellow  color. 

The  presence  of  tin  obstructs  the  cupellation,  an  infusible 
dross  of  binoxide  of  tin  being  formed  upon  the  surface. 
Silver  may  also  be  detected  in  bismuth  by  cupellation. 

264.  Silver  is  very  easily  reduced  to  the  metallic  state 
before  the   blowpipe,  but  a  sharp  heat  is  required  to  fuse  it 
into  a  globule,  which  is  then  easily  distinguished  from  all 
other  metals,  by  its  retaining  its  bright  metallic  surface  when 
fused  at  the  point  of  the  outer  (oxidizing)  flame,  and  by  its 
characteristic  white  color.     The  surface  of  the  silver  globule 
is  generally  rough  and  frosted  after  cooling,  in  consequence 
of  the  disengagement  of  occluded  oxygen  in  the  act  of  solidi- 
fying, but  it  acquires  a  strong  metallic  lustre  when  rubbed. 

The  compounds  of  silver  most  commonly  met  with  have 
been  described  at  (12). 

When  Chloride  of  Silver  is  fused  with  carbonate  of  soda 
on  charcoal,  the  surface  of  the  latter  generally  becomes  COM  ted 
with  a  white  incrustation  due  to  the  condensation  of  some 
vapor  of  chloride  of  sodium. 

265.  Detection  of  Copper  in  Silver. — Cupel  a  small  piece 
of  the  silver  with  a  piece  of  pure  lead,  as  directed  at  (263), 
when  the  copper  will  be  recognized  by  the  green  stain  pro- 
duced on  the  surface  of  the  bone-ash. 

Silver  containing  copper  is  blackened  when  heated  in  the 


REDUCTION  OF  TIN  ON  CHARCOAL.         207 

outer  blowpipe-flame,  becoming  covered  with  a  film  of  black 
oxide  of  copper. 

266.  It  is  not  easy  to  obtain  a  large  globule  of  tin  by 
fusion  on  charcoal  with  carbonate  of  soda.  An  infusible 
mass  is  commonly  formed,  which  can  only  be  reduced  by  re- 
peated addition  of  carbonate  of  soda  and  protracted  blowing. 
Minute  globules  of  tin  are  then  easily  perceived  in  the  liquid 
mass,  but  these  are  invisible  when  the  slag  has  solidified  on 
cooling.  By  levigating  the  mass  (p.  192)  large  spangles  of 
tin  may  be  obtained. 

If  there  be  any  reason  for  suspecting  the  presence  of  tin, . 
it  is  advisable  to  employ  coarsely-powdered  cyanide  of  potas- 
sium instead  of  carbonate  of  soda,  when  a  very  liquid  slag  is 
obtained,  in  which  a  large  globule  of  tin  maybe  formed  with- 
out difficulty.  The  cyanide  of  potassium,  KCN,  abstracts 
the  oxygen  and  is  converted  into  cyanate  of  potash,  KCNO. 
Cyanide  of  potassium  covers  the  charcoal  with  a  white 
incrustation. 

When  cyanide  of  potassium  is  not  at  hand,  powdered  ferro- 
cyanide  of  potassium  (yellow  prussiate  of  potash)  may  be  sub- 
stituted for  it,  but  the  globules*  of  tin  then  obtained  will  be 
rather  harder  and  less  fusible,  on  account  of  the  presence  of 
a  little  iron.  A  slight  yellow  incrustation  will  also  be  per- 
ceived on  the  surface  of  the  charcoal. 

The  chief  compounds  of  tin  have  been  described  at  (23) 
and  (37).  When  metallic  tin  is  heated  on  charcoal  before 
the  blowpipe,  it  yields  a  decided  incrustation  which  is  yellow 
while  hot  and  white  on  cooling,  and  might  lead  this  metal  to 
be  mistaken  for  zinc,  but  further  examination  prevents  the 
error  (267).  This  only  happens  when  the  unprotected  tin 
is  exposed  directly  to  the  strong  current  of  the  blowpipe 
flame  ;  when  covered  with  slag,  tin  is  remarkably  fixed  even 
at  a  very  high  temperature,  and  hence  yields  little  or  no  in- 
crustation. 

Tin-plate  (sheet-iron  coated  with  tin)  is  at  once  recognized 


20<s 


BLOWPIPE    TEST    FOR    ZINC. 


before  the  blowpipe  by  the  infusibility  of  the  iron,  the  tin 
readily  fusing  and  oxidizing  upon  its  surface. 

267.  Zinc,  being  easily  converted  into  vapor  at  a  bright 
red  heat,  does  not  yield  a  metallic  globule  before  the  blow- 
pipe, but  the  formation  of  the  yellow  incrustation  which  is 
white  on  cooling  enables  this  metal  to  be  easily  detected.  By 
moistening  the  incrustation  with  weak  solution  of  nitrate  of 
cobalt,  and  heating  intensely,  the  green  compound  of  oxides 
of  cobalt  and  zinc  may  be  produced. 

Compounds  of  zinc,  fused  with  carbonate  of  soda,  yield 
eventually  an  infusible  mass  which  is  brilliantly  incandescent, 
that  is,  emits  a  white  light  (with  a  greenish  tinge)  when  in 
the  flame.  This  mass  is  yellow  while  hot  and  becomes  white 
as  it  cools,  and  if  it  be  moisened  with  nitrate  of  cobalt  (245), 
and  again  intensely  heated,  it  becomes  bright  green. 

The  principal  compounds  of  zinc  have  been  described  at 
(53).  Metallic  zinc  burns  explosively  when  heated  on  char- 
coal with  the  blowpipe,  yielding  thick  white  fumes  of  oxide 
of  zinc. 


TABLE  T. 
268.  Colored  Beads  with  Borax. 


In  outer  flame. 

la  inner  flame. 

Chromium... 
Cobalt  

Yellowish-green  glass.. 
Blue  °"lass  

Emerald  green  glass  (269). 
Blue  (270). 

Copper  

Blue  glass  

Brown  or  colorless  (271). 
Bottle  °reen  (272) 

Manganese 
Nickel  

Purple  or  pink  glass  ... 
Brownish-yellow  glass 

Colorless  (273). 
Muddy  gray  (274). 

NOTES  TO  TABLE  T. 

269.   Should  the  color  of  the  borax-bead  leave  any  doubt 
as  to  the  presence  of  chromium,  apply  the  following  test : — 


BORAX-BEADS.  209 

Moisten  the  loop  of  platinum  wire  in  the  mouth,  dip  it  into 
dried  carbonate  of  soda,  and  fuse  this  into  a  bead,  repeating 
the  operation  if  necessary  until  the  bead  fills  the  loop.  (The 
bead  of  carbonate  of  soda  becomes  opaque  on  cooling.)  Heat 
the  bead  to  redness,  and  take  upon  it  a  little  nitrate  of  potash 
and  a  particle  of  the  substance  under  examination.  Fuse  it 
for  a  few  moments  in  the  outer  blowpipe-flame.  If  chromium 
be  present,  a  bright  yellow  opaque  bead  will  be  formed,  owing 
its  color  to  the  chromate  of  soda. 

Should  the  bead  have  a  blue  color  (green  when  hot),  it  is 
due  to  manganate  of  soda,  and  indicates  the  presence  of  man- 
ganese. 

The  compounds  of  chromium  commonly  met  with  have 
been  described  at  (61). 

The  yellowish  tinge  of  the  chromium  borax-bead  in  the 
outer  flame  is  due  to  the  presence  of  a  little  chromic  acid, 
CrO3,  which  becomes  reduced  to  chromic  oxide,  O2O3,  in 
the  inner  flame. 

270.  The  coloring  power  of  cobalt  is  very  intense,  and 
beginners  often  take  so  large  a  quantity  of  the  substance 
upon  the  bead  that  a  black  opaque  glass  is  obtained. 

The  presence  of  a  little  iron  renders  the  cobalt  bead  green 
while  hot. 

By  reduction  on  charcoal  and  levigation  (241)  many  of  the 
compounds  of  cobalt  may  be  made  to  yield  grains  of  metallic 
cobalt  which  might  be  mistaken  for  iron,  but  they  are  dis- 
solved by  a  mixture  of  hydrochloric  and  nitric  acids  to  a  blue 
or  green  solution,  which  becomes  pink  when  diluted. 

The  principal  compounds  of  cobalt  have  been  described  at 
(47). 

Cobalt  ores  generally  contain  arsenic,  sulphur,  bismuth, 
copper,  iron  and  nickel,  as  well  as  cobalt, 

IS* 


210  BLOWPIPE    TEST    FOR    COPPER. 

271.  The  bead  furnished  by  copper  in  the  outer  flame  is 
green  while  hot,  and  becomes  blue  on  cooling,  but  the  shade 
of  blue  is  very  different  from  that    given    by  cobalt.     To 
render  the  glass  colorless  in  the  inner  flame,  it  is  necessary 
that    the    bead    should    not    be    very  highly  charged  with 
copper, .and  should  be  exposed  just  in  the  hottest  part,  at  the 
extremity  of  the  inner  flame,  so  that  the  reduced  copper  may 
fuse  into  a  small  bead  and  attach  itself  to  the  wire.     If  there 
be  too  much  copper,  or  the  bead  be  not  sufficiently  heated, 
the  bead  will  assume  an   opaque  brown  color,  due  to  the 
separation  of  minute    particles    of   copper    throughout    the 
mass. 

If  a  small  particle  of  cyanide  of  potassium  be  taken  upon 
the  hot  bead  of  borax  which  has  been  charged  with  a  com- 
pound of  copper  in  the  outer  flame,  and  the  bead  be  then 
held  for  a  second  or  two  in  the  smokeless  part  of  the  ordi- 
nary flame,  it  at  once  becomes  opaque  brown,  and  if  now 
fused  in  the  outer  blowpipe-flame,  it  becomes  opaque  blue 
after  cooling. 

The  presence  of  copper  should  always  be  confirmed  by 
reduction  on  charcoal  with  carbonate  of  soda. 

The  chief  compounds  of  copper  have  been  described  at 
(27). 

272.  The  colors  assumed  by  the  iron-bead  in  the  outer 
and  inner  flames  will  be  found  to  vary  much  with  the  quan- 

.  tity  of  iron  present. 

The  brownish-yellow  glass  obtained  in  the  outer  flame 
fades  very  much  on  cooling,  so  that  if  little  iron  is  present 
it  often  becomes  colorless. 

Since  iron  is  often  found  in  small  quantity  in  substances 
of  which  it  is  not  the  most  important  ingredient,  the  analyst 
must  use  some  judgment  in  arriving  at  a  conclusion  with 
respect  to  the  real  nature  of  the  substance. 

The  principal  compounds  of  iron  are  described  at  (45). 
Sulphate  of  iron,  when  strongly  heated  in  a  small  tube 


BORAX-BEADS.  .  211 

closed  at  one  end  (17),  evolves  thick  white  vapors  of  sul- 
phuric acid,  which  strongly  redden  blue  litmus,  and  are 
accompanied  by  an  odor  of  sulphurous  acid.  The  residue 
left  after  strongly  heating  will  exhibit,  when  cold,  the  cha- 
racteristic red  color  of  colcothar. 

2J13.  Manganese  has  so  great  coloring  power  that  even 
a  small  quantity  will  often  render  the  glass  opaque.  In  order 
to  obtain  a  colorless  glass  in  the  inner  flame,  tlie  bead  must 
be  held  just  at  the  point  of  a  good  inner  flame,  and  the  de- 
coloration of  this  glass  affords  a  good  test  of  the  skill  of  the 
operator  in  preserving  the  distinction  between  the  two  flames. 
If  the  bead  be  carefully  observed  whilst  in  the  reducing 
flame,  it  will  be  seen  to  become  streaky,  and  at  the  moment 
of  the  disappearance  of  these  streaks  the  bleaching  will  be 
found  complete. 

If  a  minute  particle  of  cyanide  of  potassium  be  taken  upon 
the  bead  of  borax  which  has  been  charged  with  manganese 
in  the  outer  flame,  and  the  bead  be  heated  for  a  second  or 
two  in  the  smokeless  part  of  an  ordinary  flame,  it  becomes 
quite  colorless. 

The  presence  of  manganese  should  be  confirmed  by  fusing 
a  small  particle  of  the  substance  with  carbonate  of  soda  and 
nitrate  of  potash  (269)  in  the  outer  flame,  when  an  opaque 
blue  bead  (manganate  of  soda)  will  be  obtained  (green  when 
hot),  which  becomes  brown  when  exposed  to  the  inner 
flame. 

The  principal  compounds  of  manganese  have  been  described 
at  (55). 

274.  The  borax  beads  of  iron  and  nickel  are  very  com- 
monly mistaken  for  each  other  by  beginners,  although  close 
observation  recognizes  the  peculiar  muddy-gray  color  pro- 
duced by  the  inner  flame  in  consequence  of  the  reduction  of 
a  portion  of  the  nickel. 

If  a  minute  particle  of  nitrate  of  potash  be  taken  up  with 
the  hot  bead,  and  the  latter  exposed  to  the  outer  flame,  it 


212  BLOWPIPE    TEST    FOR    NICKEL. 

assumes  a  purple  tint  due  to  the  formation  of  borate  of  nickel 
and  potassium. 

The  ordinary  compounds  of  nickel  have  been  described 
at  (49). 

Most  nickel  ores  contain  arsenic,  sulphur,  copper,  iron  and 
cobalt,  as  well  as  nickel,  and  since  the  cobalt  has  much  more 
coloring  power  than  nickel,  it  is  rarely  that  the  latter  metal 
can  be  detected  in  the  ore  by  the  blowpipe. 

Nickel-speiss  is  a  compound  of  arsenic,  sulphur,  nickel,  and 
often  iron  and  copper,  obtained  in  the  preparation  of  smalt- 
blue  from  cobalt  ores.  It  is  a  dark -gray  or  greenish -gray 
mass  having  a  metallic  lustre.  The  arsenic  and  sulphur  can 
be  recognized  by  the  odor  evolved  when  the  substance  is 
roasted  on  charcoal  at  the  point  of  the  outer  flame. 


TABLE  U. 
275.  Colored  Flames. 


Barium 

Calcium  (lime) 

Copper 

Potassium 

Sodium...' , 

Strontium... 


Green  flame*  (276). 
Red  (277). 
Bluish-green*  (258). 
Violet  bluef  (279). 
Yellow  (280). 
Carmine  (281). 


*  Boracic  acid  also  tinges  the  flame  green,  though  of  a  different 
shade  from  that  produced  by  barium  or  copper.  The  distinctive 
characters  of  boracic  acid  are  given  at  (117).  Zinc  gives  a  green- 
ish tint  to  the  flame,  and  is  sometimes  mistaken  for  barium  by 
beginners  (267). 

f  Arsenic  gives  a  livid  blue  color  to  the  flame,  which  is  mistaken 
by  beginners  for  that  produced  by  potassium  ;  a  white  smoke  of 
arsenious  acid  issues  from  the  arsenic  flame. 


BLOAVPIPE    ANALYSIS.  213 

NOTES  TO  TABLE  U. 

276.  A  beginner  very  often  fails  to  obtain  the  green 
flame  of  barium,  especially  when  operating  upon  the  sulphate. 
To  insure  success,  it  is  \vell  to  mix  a  little  of  the  substance 
to  a  paste  with  a  drop  of  concentrated  hydrochloric  acid,  and 
to  take  a  very  little  of  this  upon  the  extremity  of  the  wire, 
which  is  then  held  in  the  point  of  a  sharp  blue  inner  flame. 
At  first  the  yellow  sodium  flame  is  generally  seen,  but  after  a 
short  time  the  grass-green  barium  flame  makes  its  appearance. 

The  green  flame  may  be  even  more  easily  obtained  by 
fusing  the  sulphate  of  baryta  with  a  bead  composed  of  fluor- 
spar fused  with  about  twice  as  much  sulphate  of  lime. 

The  tint  of  the  barium  flame  is  very  different  from  that 
given  by  copper,  and  copper  should  already  have  been  ex- 
cluded by  the  tests  on  charcoal,  and  with  the  borax-bead. 

The  commonest  compounds  of  barium  have  been  described 
at  (65). 

277.  It  is  not  easy  to  distinguish  between  the  flames  of 
calcium  and  strontium,  unless  they  are  seen  side  by  side.     By 
comparing  the  color  imparted  to  "the  flame  by  nitrate  of  stron- 
tia,  with  that  caused  by  the  substance  under  examination,  the 
danger  of  error  is  much  diminished. 

278.  The  compounds  of  calcium  or  lime  ordinarily  met 
with  have  been  described  at  (G9). 

Sulphate  of  Lime  may  be  recognized  by  mixing  it  with  an 
equal  quantity  of  powdered  fluor-spar  (fluoride  of  calcium), 
and  heating  on  a  loop  of  platinum  wire,  when  it  fuses  easily 
to  a  clear  glass,  which  becomes  opaque  on  cooling. 

Phosphate  of  Lime  may  be  identified  by  moistening  it  with 
a  drop  of  strong  sulphuric  acid,  and  exposing  it,  on  platinum 
wire,  to  the  inner  blowpipe-flame,  when  the  phosphoric  acid 
undergoes  reduction,  and  the  phosphorus  imparts  a  peculiar 
livid  greenish  hue  to  the  outer  flame. 

If  phosphate  of  lime  be  heated  in  a  small  tube  (17)  with 
metallic  magnesium,  and  the  mass,  after  cooling,  be  moistened 


214  BLOWPIPE    TEST    FOR    SODIUM. 

with   water,  it  evolves  the  peculiar  fishy  odor  of  phospho- 
retted  hydrogen. 

Fluoride  of  Calcium,  when  heated  on  a  knife,  or  on  a  piece 
of  platinum  foil,  generally  crackles  (decrepitates)  and  emits  a 
peculiar  blue  light  resembling  a  pale  flame  of  sulphur.  When 
mixed  with  an  equal  quantity  of  sulphate  of  lime  and  heated 
on  a  loop  of  platinum  wire  it  fuses  easily  to  a  clear  glass, 
which  becomes  opaque  on  cooling. 

279.  The  violet-blue  flame   of  potassium   is  easily  ob- 
scured toy  the  yellow  sodium-flame.     To  avoid  error  from 
this  cause,  the  flame  should  be  examined  through  a  square 
of  cobalt-blue  glass,  through  which  the  yellow  rays  of  the 
sodium-flame  are  not  transmitted. 

The  common  compounds  of  potassium  have  been  described 
at  (77). 

Nitrate  and  Chlorate  of  Potash  would  cause  vivid  combus- 
tion (deflagration)  when  heated  on  charcoal. 

Bisulphate  of  Potash  gives  thick  suffocating  fumes  of 
sulphuric  acid  when  heated  before  the  blowpipe  on  char- 
coal. 

Bitartrate  of  Potash  emits  the  characteristic  smell  of  burnt 
sugar  when  heated  before  the  blowpipe. 

Ferrocyanide  of  Potassium  (yellow  prussiate  of  potash) 
evolves  an  odor  of  ammonia  when  heated. 

280.  Since    almost    every    substance    contains    enough 
sodium  to  impart  a  yellow  tinge  to  the  flame,  the  analyst 
must  hesitate  before  deciding  that  sodium  is  an  essential  con- 
stituent of  the  substance  under  examination.      In  order  to 
warrant  such  a  conclusion,  the  substance  must  impart  a  very 
strong  and  persistent  yellow  color  to  the  flame. 

It  should  also  be  carefully  examined  for  those  characters 
which  are  described  at  (80)  as  belonging  to  the  ordinary 
compounds  of  sodium. 

Chloride  of  Sodium  usually  crackles  (decrepitates)  when 
heated. 


EXAMPLES    FOR    PRACTICE.  215 

Nitrate  of  Soda  causes  vivid  combustion  {deflagration) 
when  heated  on  charcoal. 

Hyposulphite  of  Soda,  when  heated,  melts  easily,  burns 
with  a  blue  flame  evolving  the  odor  of  burning  sulphur,  and 
leaves  a  brown  residue  of  sulphide  of  sodium. 

Biborate  of  Soda  would  be  identified  by  its  yielding  a 
borax-bead  on  a  loop  of  platinum  wire. 

Tungstate  of  Soda,  Na2WO4.2Aq.,  may  be  recognized  by 
fusing  it  with  a  bead  of  borax,  to  which  the  tungstic  acid 
imparts  a  pale-yellow  color  in  the  outer  flame,  becoming 
indigo-blue  in  the  inner  flame. 

281.  The  precaution  recommended  in  (277)  should  be 
taken  in  order  to  avoid  mistaking  calcium  for  strontium. 

The  chief  compounds  of  strontium  have  been  described  at 
(67). 

282.  EXAMPLES  FOR  PRACTICE  IN  EXERCISE  XVI.  (See 

10.) 


Arsenious  acid 
Chloride  of  ammonium 
Binoxide  of  tin 
Red  lead 

Chloride  of  silver 
Oxide  of  antimony 
Oxide  of  nickel 
Chloride  of  barium 
Carbonate  of  lime 
Calomel 
Oxide  of  zinc 
Oxide  of  copper 


Colcothar  (peroxide  of  iron) 
Oxide  of  bismuth 
Binoxide  of  manganese 
Oxide  of  cobalt 
Nitrate  of  stroiitia 
Nitrate  of  potash 
Carbonate  of  soda 
Lead  containing  silver  and 

copper* 

Oxide  of  chromium 
Alum 
Sulphate  of  magnesia. 


*  Obtained  by  melting  a  pound  of  lead  in  a  crucible  with  a  little 
borax,  dissolving  a  shilling  in  it,  casting  the  alloy  into  a  thin  plate, 
on  a  stone,  and  cutting  it  up  into  fragments. 


210 


TABLE    V. 


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TABLE    W. 


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Brown  vapor 
Characteristic 

Effervescence 

Extremely  pni 
Corrosion  of  t 

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Hydrofluoric 

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218  BLOWPIPE    TESTS    FOR    CHLORIDES. 


NOTES  TO  TABLE  W. 

285.  In  performing  this  test,  it  is  seldom  requisite  to 
apply  the   blowpipe-flame.      The   tube  should  be   held,   as 
represented   in  fig.  83,   in   the  lower  part  of  an  ordinary 
flame. 

Bisulphate  of  potash,  when  raised  to  a  moderately  high 
temperature,  evolves  vapor  of  sulphuric  acid.  The  analyst 
should  familiarize  himself  with  the  smell  of  the  vapor  ob- 
tained by  heating  the  bisulphate  of  potash,  before  proceed- 
ing to  draw  a  conclusion  from  this  test. 

The  action  of  the  bisulphate  of  potash  is  due  to  its  power- 
fully acid  character,  which  enables  it  to  expel  acids  from 
their  compounds,  at  a  high  temperature,  much  in  the  same 
way  as  strong  sulphuric  acid  itself. 

286.  If  a  little  black  oxide  of  manganese  or  nitrate  of 
potash    be  mixed  with    the   bisulphate  of  potash    and    the 
suspected  chloride,  it  will  evolve  chlorine  itself  on  applying 
heat,  which  may  be  recognized  by  its  odor  and  its  power  of 
bleaching  test-papers. 

The  following  blowpipe  test  is  also  sometimes  employed 
for  the  detection  of  a  chloride : — 

Make  a  bead  of  metaphosphate  of  soda  by  fusing  micro- 
cosmic  salt  (phosphate  of  soda  and  ammonia)  in  a  loop  of 
platinum  wire,  as  in  the  borax-bead  test;*  take  upon  this 
some  black  oxide  of  copper,  and  fuse  it  in  the  outer  flame  of 
the  blowpipe.  The  bead  has  a  dark -blue  color,  and  does 
not  impart  any  blue  or  green  color  to  the  outer  flame  when 
held  in  the  inner  flame.  If  a  small  quantity  of  a  chloride  be 
taken  up  on  the  hot  bead,  it  will  color  the  outer  flame  green 
or  blue,  when  held  in  the  inner  flame,  in  consequence  of  the 
formation  of  chloride  of  copper.  Sulphate  of  copper  may  be 

*  The  loop  should  be  made  double  to  enable  the  microcosmio 
salt  to  hang  to  it  better  while  being  fused. 


BLOWPIPE    ANALYSIS.  219 

substituted  for  the  oxide,  but  the  color  is  then  usually 
limited  to  a  bright-blue  halo  immediately  around  the  bead. 
Bromides  and  iodides  would  produce  a  similar  result,  but 
they  would  evolve  bromine  and  iodine,  respectively,  when 
fused  with  bisulphate  of  potash. 

The  description  of  the  principal  chlorides  will  be  found  on 
referring  to  the  index. 

287.  If  a  little  chloride  of  sodium   (common  salt)   be 
added  to  the  mixture  of  bisulphate  of  potash  with  the  sus- 
pected nitrate,  chlorine  will  be  evolved,  and  may  be  recog- 
nized by  its  peculiar  odor   and    power   of  bleaching   test- 
papers. 

If  a  nitrate  is  heated  upon  charcoal,  it  causes  vivid  com- 
bustion (deflagration). 

All  nitrates  except  those  of  potash,  soda,  and  ammonia, 
evolve,  sooner  or  later,  brown  vapor  of  nitric  peroxide,  with 
its  peculiar  odor,  when  heated  in  a  tube,  by  themselves. 

The  description  of  the  principal  nitrates  will  be  found  on 
referring  to  the  index. 

The  ordinary  saltpetre  of  commerce  contains  chlorides  of 
potassium  and  sodium,  and  therefore  evolves  some  chlorine 
when  heated  with  bisulphate  of  potash. 

288.  The  carbonates  are  of  course  far  more  easily  recog- 
nized by  their  effervescence  when  moistened  with  hydrochloric 
acid  in  the  colored  flame  test  (244). 

289.  The  odor  of  hydrofluoric  acid  is  far  more  painfully 
pungent  than  that  of  hydrochloric  acid. 

On  breathing  upon  the  mouth  of  the  tube,  a  little  opaque 
silica  is  deposited  on  the  glass,  from  the  decomposition,  by 
moisture,  of  fluoride  of  silicon  resulting  from  the  action  of 
the  hydrofluoric  acid  upo  i  the  silica  in  the  glass. 

The  corrosion  of  the  tube  is  indicated  by  its  peculiar 
greasy  appearance,  but  can  only  be  fully  seen  after  the  tube 
has  been  well  washed  and  dried. 

Fluor-spar  (fluoride  of  calcium)  and  kryolite  (fluoride  of 
aluminium  and  sodium)  are  the  only  fluorides  commonly  met 


220  BLOWPIPE    ANALYSIS. 

with  in  blowpipe  analysis,  and  have  been  described  at  (59) 
and  '(89). 

290.  It  must  be  remembered  that  chlorine  would  also  be 
evolved  from  a  chloride  mixed  with  some  oxidizing  agent 
(287). 

Chlorates,  heated  on  charcoal,  cause  vivid  combustion 
(deflagration). 

The  chlorates,  when  moderately  heated  by  themselves,  in 
a  small  tube,  evolve  oxygen,  recognized  by  its  power  of  ac- 
celerating the  combustion  of  a  spark  at  the  end  of  a  match 
when  held  in  the  mouth  of  the  tube. 

The  only  chlorates  at  all  commonly  met  with,  those  of 
potash  and  baryta,  have  been  described  at  pp.  82  and  70. 

Hypochlorite  of  lime,  the  only  hypochlorite  likely  to  be 
met  with,  has  been  described  at  p.  74. 

291.  Any  doubt  about  the  presence  of  iodine  could  be  set 
at  rest  by  exposing  to  the  vapor  a  piece  of  cotton  or  paper 
which  has  been  starched ;  this  would  be  colored  intensely 
blue  by  the  iodine,   if  previously  moistened.     Iodine  itself 
would  be  recognized  by  heating  it  in  a  tube,  when  it  would 
fuse  and   be  entirely  converted  into  violet  vapor,  condensing 
in  black  shining  scales  on  the  side  of  the  tube.     The  prin- 
cipal iodides  will  be  found  on  referring  to  the  index.- 

292.  If  a  piece  of  moistened  starched  paper  or  cotton  be 
exposed  to  the  vapor  of  bromine,  it  acquires  a  fine  yellow 
color. 


TABLE    X. 


221 


TABLE  X. 

293.  Heating  in  small  tube  for  Non-metals 
and  Acids. 


Acid  vapors   are 
evolved  without 
carbonization. 

Either   sulphuric,   hydrochloric,   nitric,   or 
oxalic  acid  is  probably  present  (294). 

Carbonization  takes 
place. 

Presence  of  some  organic  matter  ;  perhaps 
tartaric  or  acetic  acid  (295). 

Brown  acid  vapors 

Presence  of  nitric  acid  (296). 

Reddish   drops    of 
sulphur  condense 
on   the    sides   of 
the  tube. 

Presence  of  sulphur  or  a  sulphide  (297). 

Violet  vapors. 

Presence  of  iodine  (298). 

Cyanogen  is  evolved, 
burning    with    a 
pink  name. 

Presence  of  a  cyanide  (299). 

Oxygen  is  evolved 
and  rekindles  a 
spark  on  the  end 
of  a  match. 

Presence  of  a  chlorate,  a  nitrate,  or  some 
easily  decomposed  metallic  oxide  (300). 

NOTES  TO  TABLE  X. 

Si94.  The  sulphates  are  affected  by  heat  in  very  different 
degrees. 

Sulphates  of  potash,  soda,  baryta,  strontia,  lime,  magnesia, 
and  lead,  would  not  yield  acid  vapors  in  this  experiment. 

19* 


222  BLOWPIPE    ANALYSIS. 

Bisulphates  of  potash  and  soda  give  strong  fumes  of  sul- 
phuric acid. 

Sulphate  of  ammonia  evolves  sulphurous  and  sulphuric 
acids,  and  is  entirely  dissipated  by  heat. 

Sulphate  of  iron  evolves  sulphurous  and  sulphuric  acids, 
leaving  a  red  residue  of  peroxide  of  iron. 

The  sulphates  of  alumina,  zinc,  manganese,  nickel,  cobalt, 
and  copper  require  a  much  higher  temperature  to  decompose 
them,  and  evolve  chiefly  sulphurous  acid. 

295.  If  tartaric  acid  be  present,  a  peculiar  smell,  like 
that  of  burnt  sugar,  is  evolved.     The  acetates  also  evolve  an 
odor  of  acetone,  which  is  rather  pleasant. 

The  tartrates  and  acetates  of  potash,  soda,  baryta,  strontia, 
and  lime,  when  heated,  leave  a  residue  composed  of  charcoal 
mixed  with  a  carbonate,  which  effervesces  with  acids,  and  in 
the  cases  of  potash  and  soda,  is  very  strongly  alkaline. 

296.  The  nitrates  of  potash  and  soda  do  not  evolve  acid 
vapors    when    heated.     Nitrate   of  ammonia    is    extremely 
fusible,  and  is  entirely  dissipated  by  heat. 

The  other  nitrates  evolve  brown  acid  vapors  when  heated. 
Nitrate  of  silver  requires  a  high  temperature  for  its  decom- 
position. 

297.  "The  smell  of  sulphur  would  be  perceived  here. 
The  only  common  sulphides  which  give  off  sulphur  when 

heated  in  a  tube  are  iron  pyrites  and  copper  pyrites. 

298.  The  smell  of  iodine  is  characteristic. 
Indigo  blue  also  gives  off  violet  vapors  when  heated. 
Iodide  of  lead  is  the  only  common  iodide  which  evolves 

iodine  vapor  when  heated  in  a  tube. 

299.  The  smell  of  cyanogen  is  very  peculiar. 

This  gas  should  burn  with  a  pink  flame  on  approaching 
the  mouth  of  the  tube  to  a  light. 

Cyanides  of  mercury  and  silver  are  the  only  ordinary  cya- 
nides which  evolve  cyanogen  when  heated. 

300.  Chlorates  yield  oxygen  more  abundantly  and  at  a 


TABLE    Y. 


223 


lower  temperature  than  the  nitrates,  and  both  salts  fuse  before 
undergoing  decomposition. 

The  metallic  oxides  would  not  fuse  before  evolving  oxygen. 
The  principal  metallic  oxides  which  give  off  oxygen  when 
heated,  are  black  oxide  of  manganese,  red  lead,  oxide  of 
mercury,  oxide  of  silver. 


TABLE  Y. 

301.  Detection  of  Non  metals  and  Acids  on 
charcoal  before  the  blowpipe. 


Nitrates 
Chlorates 

Deflagrate,  that  is,  cause  vivid  combustion  of 
the  charcoal. 

Sulphides 

Evolve  the  odor  of  sulphurous  acid  when  roasted 
alone  in  the  outer  flame. 
Yield  a  brown  fused  mass  with  carbonate  of  soda 
in  the  inner  flame. 

Silicates 
Borates 

Yield  with  carbonate  of  soda  a  bead  of  glass 
which  is  not  absorbed  by  the  charcoal  (242). 

224 


TABLE    Z. 


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BLOWPIPE    TESTS    FOR    SULPHUR    AND    SILICA.        225 


NOTES  TO  TABLE  Z. 

303.  As  this  test  depends  upon  the  formation  of  sulphide 
of  sodium,  any  compound  containing  sulphur  would  furnish 
the  same  result,  so  that  the  analyst,  before  concluding  that 
the  substance  under  examination  is  a  sulphate,  must  take  its 
general  characters  into  consideration. 

The  presence  of  sulphide  of  sodium  in  the  fused  mass  is 
detected  with  greater  delicacy  by  dissolving  it,  on  a  crucible- 
lid  or  in  a  small  capsule,  in  a  few  drops  of  water,  and  adding 
a  little  nitroprusside  of  sodium,  Na2FeNO5CN,  which  gives 
a  fine  purple  color. 

The  following  is  also  a  delicate  blowpipe  test  for  sulphur : 
Make  a  small  bead  of  pure  carbonate  of  soda  on  a  platinum 
loop  (269),  and  take  successive  portions  of  pure  silica  upon 
it,  until  the  fused  bead  remains  transparent  after  cooling. 
The  bead  should  now  remain  colorless  even  when  heated  in 
the  reducing  flame,  but  if  a  partible  of  a  substance  containing 
sulphur  in  any  form  be  added  to  it,  it  will  assume  a  brown 
yellow  color  in  the  reducing  (inner)  flame,  due  to  the  forma- 
tion of  sulphide  of  sodium. 

In  very  exact  analysis,  a  gas-  flame  must  not  be  employed 
in  testing  for  sulphur,  since  this  element  is  always  present  in 
coal-gas,  and  is  absorbed  from  the  flame  by  the  carbonate  ot 
soda.  The  flame  of  a  spirit  or  oil  lamp  is  free  from  sulphur. 

304.  This  test  requires  some  patience,  since  it  is  neces- 
sary to  repeat  the  addition  of  silicic  acid  many  times  in  order 
to  obtain  a  transparent  glass  of  silicate  of  soda.     The  glass 
is  often  colored  yellow  by  the  presence  of  a  little  sulphide  of 
sodium  (see  303). 

Boracic  acid  would  also  render  a  bead  of  carbonate  of  soda 
transparent,  but  the"  following  test  will  prevent  mistakes. 
Make  a  bead  with  microcosmic  salt  (286),  which  is  perfectly 


221)  BLOWPIPE    TEST    FOR    PHOSPHORIC    ACID. 

transparent.  The  bead  thus  obtained  will  dissolve  nearly 
every  other  substance  but  silica,  so  that  particles  of  that 
substance  may  be  seen  floating  about  undissolved  in  the 
fused  bead. 

305.  This  extremely  delicate  test  for  boracic  acid  depends 
upon  the  production  of  fluoride  of  boron,  by  the  action  of  the 
hydrofluoric  acid  resulting   from  the  decomposition  of  the 
fluor-spar   by  the    bisulphate   of  potash.     The   fluoride   of 
boron  tinges  the  outer  flame  green.      If  much  sodium  be 
present,  the  green  color  is  not  easily  perceived. 

If  a  platinum  wire  be  moistened  with  glycerin  and  a 
powdered  borate  be  taken  upon  it,  a  distinct  green  tinge  will 
be  imparted  to  the  flame  when  the  glycerin  is  kindled.  The 
presence  of  sodium  does  not  prevent  the  color  from  being 
seen. 

Borax  (biborate  of  soda)  would  be  easily  recognized  by 
its  behavior  when  heated  on  a  loop  of  platinum  wire. 

306.  In   this   test,  the  phosphoric  acid  set  free  by  the 
action  of  sulphuric  acid  is  deoxidized  by  the  flame,  and  the 
vapor  of  phosphorus  which  is  produced  imparts  the  peculiar 
livid  tinge  to  the  outer  flame. 

This  test  does  not  give  a  satisfactory  result  when  much 
sodium  is  present. 

If  a  compound  containing  phosphoric  acid  be  heated  in  a 
tube  (17)  with  a  little  metallic  magnesium,  and  the  mass, 
after  cooling,  be  moistened  with  water,  the  peculiar  fishy 
odor  of  phosphoretted  hydrogen  will  be  perceived. 

The  following  is  the  most  conclusive  blowpipe  test  for 
phosphoric  acid  : — 

Mix  the  compound  to  be  tested  with  two  or  three  parts  of 
dried  boracic  acid,  arid  fuse  it  in  a  cavity  scooped  in  charcoal. 
Thrust  into  the  melted  mass  about  half  an  inch  of  very  thin 
iron  wire  (of  which  twelve  inches  weigh  one  grain)  and  heat 
it  for  two  or  three  minutes  in  a  powerful  reducing  flame.  If 
phosphoric  acid  be  present,  a  hard  silvery  brittle  metallic 
globule  of  iron  containing  phosphorus  will  be  formed,  which 


EXAMPLES    FOR    PRACTICE. 


227 


may  be  extracted  from  the  fused  mass  by  wrapping  it  in  stout 
paper  and  striking  it  with  a  hammer  upon  the  anvil. 


307.  EXAMPLES   FOR  PRACTICE  IN  EXERCISE  XVII. 
(10). 


Chloride  of  sodium 
Carbonate  of  soda 
Chlorate  of  potash 
Bitartrate  o'f  potash 
Nitrate  of  lead 
Cyanide  of  mercury 
Silica  (white  sand) 
Sulphate  of  baryta 


Nitrate  of  potash 

Fluor-spar 

Iodide  of  potassium 

Acetate  of  lead 

Iron  pyrites 

Sulphide  of  iron 

Boracic  acid 

Phosphate  of  lime  (bone-ash). 


228  TESTS    USED    IN    ANALYSIS. 


ALPHABETICAL  LIST  OF  THE  PRINCIPAL 
TESTS  OR  REAGENTS. 

308.  ACETATE    OF    LEAD,    or     PLUMBIC    ACETATE 
Pb2C.2H3O2,  may  be  obtained  at  oil  and  color  shops  as  sugar 
of  lead  (14).     One  ounce  is  sufficient.     To  prepare  the  solu- 
tion, shake  half  an  ounce  with  five  measured  ounces  of  dis- 
tilled or  rain  water,  until  dissolved,  with  the  exception  of  a 
little  white  carbonate  of  lead  which  may  be  filtered  off. 

Scraps  of  lead  partly  covered  with  vinegar,  in  an  open 
bottle,  will  give  a  solution  of  acetate  of  lead  in  the  course  of 
a  few  hours. 

Acetate  of  Lead  is  a  test  for 

Sulphuretted  hydrogen       .     .     Black  precipitate  (97) 

Chromic  acid Yellow  precipitate  (120) 

Iodides Yellow  precipitate  (93). 

309.  ACETIC  ACID,  C2H4O2,  is  the  acid  of  vinegar,  and 
is  sold  by  druggists  in  a  diluted  state  (149).     Four  ounces 
will  suffice.     It  must  not  give  any  precipitate  when  mixed 
with  excess  of  ammonia  (5)  and  sulphide  of  ammonium. 

By  boiling  vinegar  with  powdered  wood-charcoal,  and 
filtering  it,  or  much  better,  by  distilling  vinegar  (227), 
acetic  acid  may  be  obtained  sufficiently  pure  for  most  pur- 
poses. 

310.  ALCOHOL  C2H6O,  of  sufficient  strength  for  ordinary 
use  iss  old  as  spirits  of  wine.     The  methylated  spirit  is  much 
cheaper,  and  answers  for  most  of  the  uses  of  alcohol  (209, 
210).     Four  ounces  (or  a  gill)  will  suffice. 

311.  AMMONIA,  NH3,  is  sold  by  the  druggists  as  liquor 
ammonia  or  hartshorn,  prepared  by  absorbing  ammoniacal 
gas  in  water  (75).     Eight  ounces  should  be  provided. 

It  must  not  give  any  precipitate  with  oxalate  of  ammonia 
(indicating  lime), and  very  little,  if  any,  with  chloride  of  cal- 
cium (indicating  carbonate  of  ammonia). 


TESTS    USED    IN    ANALYSIS.  229 

Ammonia  is  a  test  for 

Copper Bright  blue  color  (26) 

Nickel Violet  blue  (48) 

Iron  (as  peroxide)      .     .     .      Red  brown  precipitate  (45) 
Mercury  (as  a  mercurious  salt)  Gray  precipitate  (13). 

312.  AXTIMONIATE    OF    POTASH,    OF     HYDROPOTASSIC 

METANTIMONIATE,  KtH8SbtOTJ  can  be  obtained  only  from  the 
operative  chemist  (39).  Two  drachms  of  the  salt  should  be 
boiled  with  five  measured  ounces  of  distilled  or  rain  water,  in  a 
flask,  for  a  few  minutes,  and  filtered.  A  drop  of  the  solution 
stirred  with  a  drop  of  carbonate  of  soda  upon  a  slip  of  glass  (fig. 
27)  should  give  a  distinct  precipitate  upon  the  lines  of  friction. 

313.  BICARBONATE  OF  SODA,  or  HYDROSODIC  CARBO- 
NATE, NaHCO3,  is  sold  by  the  druggist  under  the  name  of 
carbonate  of  soda,  in  the  form  of  powder  (80).     One  ounce 
should  be  placed  in  the  bottle,  and  shaken  with  eight  meas- 
ured ounces  of  cold  distilled  or  rain  water. 

BICHLORIDE  OF  MERCURY;  see  PERCHLORIDE  OF  MER- 
CURY. 

314.  BICHLORIDE  OF  PLATINUM,  or  PLATINIC  CHLO- 
RIDE, PtCl4  (also  called  chloride  and  perchloride  of  platinum 
and  muriate  of  platina),  may  be  obtained  from  the  operative 
chemist,  generally  in  the  form  of  a  solution  in  water.     It  is 
expensive.    Half  an  ounce  will  suffice.    It  should  give  a  well 
marked  precipitate  when  stirred  upon  a  slip  of  glass  with  a 
drop  of  a  moderately  strong  solution  of  nitrate  of  potash  (76). 

To  prepare  bichloride  of  platinum,  dissolve  10  grains  of 
scrap  platinum  (or  old  platinum  foil)  in  a  flask,  by  gently 
heating  it  with  two  measured  drachms  of  strong  hydrochloric 
acid,  and  half  a  drachm  of  strong  nitric  acid.  Pour  the  solu- 
tion into  a  dish,  and  evaporate  it  at  a  gentle  heat  (fig.  30) 
till  it  becomes  a  syrup  which  solidifies  on  cooling.  Dissolve 
this  in  an  ounce  and  a  half  of  distilled  or  rain  water. 

315.  BICHROMATE  OF  POTASH,  or  POTASSIC  BICHRO- 
MATE, K2O.2CrO3,  is  sold  by  the  operative  chemist  in  crys- 

20 


230  TESTS    USED    IN    ANALYSIS. 

tals  (61).  Half  an  ounce  of  the  crystals  may  be  dissolved  in 
eight  measured  ounces  of  hot  distilled  water. 

316.  BlSULPHATE  OF  POTASH,  Or  HYDROPOTASSIC  SlJL- 

PHATE,  KHS04,  is  sold  in  a  crystalline  form  by  the  operative 
chemist  (77).  It  is  only  required  for  blowpipe  analysis. 
One  ounce  will  suffice.  It  is  generally  made  in  the  labora- 
tory from  the  residue  left  in  preparing  nitric  acid. 

317.  BoNE-AsH  is  made  by  burning  bones  white  in  a 
clear  fire,  and  grinding  the  ash  to  a  fine  powder  (56).     It  is 
sold  by  the  operative  chemist,  and  is  only  required  for  blow- 
pipe analysis. 

318.  BORACIC  ACID,  H3BO3,  is  generally  sold  by  the 
operative  chemist  in  the  crystallized  form  (117).     It  is  only 
used  in  blowpipe  analysis.     Half  an  ounce  of  the  crystals 
should  be  dried  in  an  evaporating  dish  placed  in  an  oven  or 
over  a  low  flame,  and  reduced  to  powder. 

319.  BORAX,  Na2O.2B2O3,  is  sold  at  the  oil-shops  in  crys- 
tals (80).     An  ounce  of  the  crystals  should  be  heated  in  an 
evaporating  dish,  over  a  moderate  flame,  till  the  spongy  mass 
ceases  to  swell  up  and  evolve  steam,  when  it  should  be  re- 
duced to  powder. 

320.  CARBONATE  OF  AMMONIA,  or  AMMONIC  SESQUI- 
CARBONATE,  2(NH4)2O.3CO2,  is  sold,  under  the  former  name, 
by    the    druggist,   in    white    lumps   (75).     Two    ounces    of 
the  salt  should  be  reduced  to  powder,  and  shaken,  in  the 
bottle,  with  six  measured  ounces  of  cold  distilled  or  rain 
water. 

321.  CARBONATE    OF    SODA,    or   SODIC    CARBONATE, 
Na2C03,  is  best  obtained,  for  use  in  analysis,  from  the  bicar- 
bonate of  soda  commonly  sold  as  a  white  powder  under  the 
name  of  Carbonate  of  Soda  (80J.     This  should  be  heated  in 
an  evaporating  dish  over  a  Bunsen  burner  (fig.  35)  for  a 
quarter  of  an  hour,  so  as  to  drive  off  half  its  carbonic  acid. 
After  cooling,  one  ounce  of  the  carbonate  may  be  dissolved  in 
six  measured  ounces  of  distilled  or  rain  water.     The  solution, 
when  acidulated  with  dilute  nitric  acid,  should  give  no  pre- 


TESTS    USED    IN    ANALYSIS.  231 

cipitate  with  nitrate  of  baryta  (indicating  sulphate  of  soda), 
or  nitrate  of  silver  (indicating  chloride  of  sodium). 

322.  CHLORIDE  OF  AMMONIUM,  or  AMMONIC  CHLORIDE, 
Nil  Cl,  is  sold  under  the  names  of  sal-ammoniac  arid  muriate 
of  ammonia,  by  the  druggist.     The  crystallized  salt  is  purer 
than  the  lumps  obtained  by  sublimation,  which  are  colored 
brown  by  iron  (75). 

Dissolve  one  ounce  of  the  salt  in  eight  measured  ounces  of 
warm  distilled  or  rain  water. 

Chloride  of  Ammonium  is  a  test  for 
Platinum  .....     Yellow  granular  precipitate. 

323.  CHLORIDE  OF  BARIUM  or  BARIC  CHLORIDE,  BaCl2, 
is  sold  by  the  operative  chemist,  as  muriate  ofbarytes,  in  crys- 
tals (65).     The  solution  is  made  by  dissolving  half  an  ounce 
of  the  salt  in  five  measured  ounces  of  distilled  or  rain  water. 

324.  CHLORIDE  OF  CALCIUM,  or  CALCIC   CHLORIDE, 
CaCl2,  may  be  obtained  from  the  operative  chemist  either  in 
crystals,  or  more  commonly  in  white  lumps  of  dried  chloride 
of  calcium  (09).     One  ounce  may  be  dissolved  in  four  mea- 
sured ounces  of  distilled  or  rain  water  for  use  as  a  test. 

Chloride  of  calcium  is  easily  made  by  adding  chalk,  or 
whitening,  or  marble,  to  dilute  hydrochloric  acid,  as  long  as 
it  is  dissolved,  boiling  the  solution  till  it  no  longer  reddens 
blue  litmus  paper,  and  filtering. 

325.  CHLORIDE  OF  LIME  may  be  purchased  at  the  oil- 
shops.     If  good,  it  is  a  dry  powder  which  has  a  strong  smell 
like  chlorine,  and  gives  off  much  chlorine  when  mixed  with 
dilute  sulphuric  acid.     To  make  the  solution  for  testing,  one 
ounce  of  the  chloride  is  rubbed  down  in  a  mortar  with  eight 
ounces  of  water,  and  filtered. 

326.  CHLORINE  WATER  is  made  by  passing  chlorine  gas 
into  water.    A  small  quantity  may  be  quickly  made  by  pour- 
ing the  gas  into  a  test-tube  half  full  of  water,  and  shaking 
violently  after  closing  the  tube  with  the  thumb.     By  pouring 
the  gas  in  three  or  four  times,  strong  chlorine  water  may  be 


232  TESTS    USED    IN    ANALYSIS. 

made  in  two  or  three  minutes.  The  gas  is  prepared  by  gently 
warming  black  oxide  of  manganese  with  strong  hydrochloric 
acid,  in  a  test-tube  or  flask. 

326a.  COPPER.  Thin  sheet  copper  in  pieces  about  half 
an  inch  long  and  an  eighth  wide ;  or  pieces  of  copper  wire 
may  be  used ;  it  may  be  brightened  by  immersion  in  nitric 
acid  and  washing. 

Copper  (when  boiled  in  a  solution  acidified  with  hydrochloric  acid) 
is  a  test  for 

Mercury Bright  silvery  coating  (30) 

Arsenic Dark  gray  "       (33) 

Antimony Purplish  "       (32) 

Bismuth Light  gray  "       (28) 

327.  CYANIDE  OF  POTASSIUM,  or  POTASSIC  CYANIDE, 
KCN,  is  sold  by  druggists  in   white  lumps   (77).      These 
should  be  coarsely  powdered  in  a  mortar.     Only  small  quan- 
tities should  be  kept  in  powder  in  a  well-closed  bottle.     It  is 
very  poisonous. 

Two  ounces  of  cyanide  of  potassium  will  suffice  for  some 
time. 

328.  ETHER,  C4H100,  may  be  obtained  from  the  druggist, 
and  must  be  kept  in  a  stoppered  bottle  (221).     One  ounce 
will  suffice.     Methylated  ether  is  less  expensive  than  pure 
ether,  and  should  be   employed  when  large  quantities  are 
required. 

329.  FERRIDCYANIDE    OF    POTASSIUM,   or   POTASSIC 
FERRIDCYANIDE,  K3FeCy6,  is  sold  by  the  operative  chemist 
in  crystals,  and  is  commonly  called  red  prussiate  of  potash  or 
ferricyanide  of  potassium  (77).    Half  an  ounce  of  the  salt  may 

be  dissolved  in  five  measured  ounces  of  distilled  or  rain  water. 

Ferridcyanide  of  Potassium  is  a  test  for 
Iron  as  a  ferrous  compound  or  protosalt  .     .  Blue  precipitate  (45). 

330.  FERROCYANIDE  OF  POTASSIUM,  or  POTASSIC  FER- 
ROCYANIDE,  K4FeCy6,  is  often  obtainable  from  the  oil  and 
color  shops  as  yelloiv  prussiate  of  potash,  in  crystals  (77).   For 


TESTS    USED    IN    ANALYSIS.  233 

testing,  half  an  ounce  of  the  salt  may  be  dissolved  in  five 
measured  ounces  of  distilled  or  rain  water. 

Ferrocijanide  of  Potassium  is  a  test  for 

Iron          ....         Blue  precipitate  (45). 
Copper     ....         Brown-red  precipitate  (27). 

331.  HYDROCHLORIC  ACID,  HC1,  may  be  obtained  from 
the  druggist  as  a  solution  of  hydrochloric  acid  gas  in  water 
(105).     Its  common  name  is  muriatic  acid.     It  should  be 
colorless,  and   strong  enough  to  emit  fumes  in   moderately 
damp  air.     Eight  ounces  of  this  acid  should  be  provided. 

Dilute  hydrochloric  acid  is  made  by  mixing  the  strong 
acid  with  twice  its  volume  of  distilled  or  rain  water. 

The  acid  must  give  no  precipitate  with  hydrosulphuric 
acid  (indicating  arsenic,  chlorine,  sulphurous  acid,  perchloride 
of  iron)  or  with  excess  of  ammonia  (5)  and  sulphide  of  am- 
monium (indicating  iron),  or  with  much  water  and  chloride 
of  barium  (indicating  sulphuric  acid). 

332.  HYDROFLUOSILICIC  ACID,  orSiLicoFLuORic  ACID, 
H2SiF6,  is  sold  by  the  operative  chemist  in  a  diluted  state. 
One  ounce  will  suffice.     It  must  not  give  any  precipitate 
with  solution  of  nitrate  of  strontia  (indicating  sulphuric  acid) 
even  on  stirring. 

333.  HYDROSULPHATE  OF  AMMONIA,  or  SULPHIDE  OF 
AMMONIUM,  (NH4)2S,  may  be  obtained  in  solution  from  the 
operative  chemist  (75).     It   must  not  give  any  precipitate 
with  sulphate  of  magnesia  (indicating  free  ammonia).     Eight 
ounces  of  the  solution  should  be  provided,  and  must  be  kept 
in  a  well-closed  bottle. 

Hydrosulphate  of  ammonia  is  easily  prepared  by  passing 
hydrosulphuric  acid  gas  (334)  into  solution  of  ammonia 
until  it  no  longer  gives  a  precipitate  with  sulphate  of  mag- 
nesia. 

334.  HYDROSULPHURIC  ACID,  H2S,is  prepared  bypass- 
ing sulphuretted  hydrogen  gas  into  water  until  the  stopper 
of  the  bottle  is  forced  up  when  the  liquid  is  shaken. 

20* 


234 


TESTS    USED    IN    ANALYSIS. 


FIG.  88. 


Fragments  of  sulphide  of  iron  (procurable  from  the  opera- 
tive chemist)  are  placed  in  a  half-pint  bottle  (6,  fig.  88), 
which  is  half  filled  with  water.  Strong  sulphuric  acid  is 
poured  down  the  funnel  tube  (f)  in  a  few  drops  at  a  time, 
until  the  bubbles  of  gas  pass  freely  through  the  wash -bottle 
(w)  which  contains  a  little  water.  The  gas  is  then  passed 
into  the  bottle  (c),  which  contains  the  distilled  water  to  be 
charged  with  gas.  Any  gas  which  is  not  absorbed  by  the 
water  passes  into  the  bottle  (eT)  containing  solution  of  am- 
monia. This  retains  all  the  gas,  and  prevents  it  from  con- 
taminating the  air.  When  this  ammonia  has  become  saturated 
with  the  gas,  so  that  it  no  longer  precipitates  sulphate  of 
magnesia,  it  may  be  used  as  hydrosulphate  of  ammonia,  but 
it  will  be  long  before  this  point  is  reached. 

About  ten  minutes  are  required  to  saturate  the  water  in 
the  bottle  (c)  with  a  brisk  current  of  gas. 

The  parts  of  this  apparatus  are  connected  by  vulcanized 
India-rubber  tubing,  which  may 
be  obtained  from  the  operative 
chemist. 

Fig.  89  shows  a  simpler  appa- 
ratus for  preparing  the  solution 
of  hydrosulphuric  acid,  but  since 
there  is  no  provision  for  absorb- 
ing the  excess  of  gas,  it  can  only 
Hydrosuiphuric  acid  apparatus,  be  used  in  a  fume.closet  with  a 


FIG.  89. 


TESTS    USED    IN    ANALYSIS.  235 


ffydrosulphuric  Acid  is  a  test  for 

Cadmium     .     .     Bright  yellow  precipitate  in  ammoniacal  solution 

Antimony    .     .     Red  precipitate  in  acid  solution  (39) 

Zinc   ....     White  precipitate  in  ammoniacal  solution  (53). 

335.  IODIDE  OF  POTASSIUM,  or  POTASSIC  IODIDE,  KI, 
is  sold  in  crystals  by  the  druggist  (77).  It  is  sometimes  called 
hydriodate  of  potash.  Two  drachms  of  the  salt  may  be  dis- 
solved in  five  measured  ounces  of  distilled  or  rain  water. 

Iodide  of  Potassium  is  a  test  for 

T      ,  (  Bright  yellow  precipitate,  dissolved 

(      by  boiling  water  (14). 

Q.,  $  Pale   yellow   precipitate,  whitened 

'    \      by  ammonia  (12). 


Mercury  as  a  mercuric  salt       *  ****** 


336.  IODINE   is  procurable  in  the  solid  form  from  the 
druggist  (93).     Five  grains  may  be  shaken  with  an  ounce  of 
water  to  prepare  iodine-water. 

Iodine-water  is  a  test  for 
Starch     .....  •  .     .     Blue  color. 

337.  LIME-WATER,  CaII2O2,  is  sold  by  the  druggist.     It 
should  turn  reddened  litmus  distinctly  blue.     It  is  prepared 
by  shaking  freshly  slaked  lime  with  distilled  or  rain  water, 
allowing  the  solution  to  settle  in  a  well-closed  bottle,  and 
pouring  off  the  clear  liquid. 

338.  LITMUS   PAPER,  both  red  and  blue,  may  be  pro- 
cured from  the  operative  chemist. 

The  coloring  matter  is  made  from  a  species  of  lichen,  the 
Rocella  t-inctoria,  and  is  sold  in  blue  cakes  made  up  with 
chalk  or  plaster  of  Paris. 

To  make  litmus  paper,  heat  half  an  ounce  of  cake  litmus 
with  three  measured  ounces  of  distilled  or  rain  water  for  half 
an  hour,  and  filter  the  solution.  To  one-half  of  it,  add  a 
little  extremely  dilute  sulphuric  acid,  on  the  end  of  a  glass 
rod,  until  it  acquires  a  faint  reddish  tinge  (by  daylight). 


236  TESTS    USED    IN*  ANALYSIS. 

Add  the  otlier  half  of  the  solution,  and  immerse,  in  the  blue 
liquid,  strips  of  white  filter-paper,  or  better,  of  unsized  draw- 
ing-paper. Hang  them  on  a  string  to  dry,  out  of  the  reach 
of  acid  fumes.  Redden  the  remaining  liquid  faintly  by  stir- 
ring with  the  rod  dipped  in  dilute  sulphuric  acid,  and  dye 
some  more  paper  with  the  solution,  to  obtain  red  litmus 
paper. 

These  papers  fade  when  exposed  to  a  strong  light. 

339.  MICROCOSMIC  SALT,  NaNH4HPO4,  is  used  only  in 
blowpipe  analysis,  and  may  be  obtained  from  the  operative 
chemist.     A  very  small  quantity  is  used. 

340.  MOLYBDATE  OF  AMMONIA,  NH4HMo04,  is  sold  by 
the  operative  chemist  in   crystals.     It  is  an  expensive  salt. 
Twenty  grains   may  be   dissolved   in  an   ounce  of  distilled 
water  for  testing. 

Molybdate  of  Ammonia  is  a  test  for    . 

Phosphoric  acid  .    i  B^t  yellow  precipitate  in  a  nitric 

(      solution,  on  warming  (111). 

341.  NITRATE    OF    BARYTA,    or    BARIC    NITRATE, 
Ba2NO3,  may  be   obtained  in   crystals  from   the  operative 
chemist  (65).     Half  an  ounce  of  the  salt  may  be  dissolved 
in  five  measured  ounces  of  distilled  or  rain  water. 

Nitrate  of  Baryta  is  a  test  for 

Snlnhuric  arid  I  Milky  wllite  precipitate  insoluble  in 

'     '    (      dilute  nitric  acid  (102). 

342.  NITRATE  OF  COBALT,  or  COBALTOUS  NITRATE, 
Co2NO3,  is  sold,   commonly  in   solution,   by  the   operative 
chemist  (47).     It  is  required  for  blowpipe  analysis  only.    A 
very  small  quantity  will  suffice. 

343.  NITRATE  OF    POTASH,   or   POTASSIC    NITRATE, 
KNO3,  is  sold  at  the  oil-shops  as  saltpetre  (77).     It  should 
be  kept,  for  use  in  analysis,  in  powder. 

344.  NITRATE    OF    SILVER,  or  ARGENTIC    NITRATE, 
AgNO3,  may  be  obtained  from  the  druggist,  in  crystals,  in 


TESTS    USED    IN    ANALYSIS.  237 

fused  sticks  (lunar  caustic)  or  in  solution  (12).  Two  drachms 
of  the  crystals  may  be  dissolved  in  five  measured  ounces  of 
distilled  water. 

Nitrate  of  Silver  is  a  test  for 


Hydrochloric  acid  or  chlorides 


Hydriodic  acid  or  iodides 


White  precipitate  insoluble  in 
boiling  nitric  acid  ;  soluble  in 
ammonia  (105). 

Yellow  precipitate  insoluble  in 
nitric  acid.  Whitened,  but  not 


dissolved  by  ammonia  (106). 
White  precipitate,  passing  rapid- 
ly through  various  shades  of 

Hyposulphites \        yellow,  red,  and  brown,  finally 

becoming    black    sulphide   of 
silver. 

345.  NITRIC  ACID,  HNO3,  may  be  obtained  from  the 
druggist  (109).     Eight  ounces  should  be  provided,  and  must 
be  kept  in  a  stoppered  bottle.     It  should  be  nearly  colorless, 
and  should  fume  moderately  when  exposed  to  air.     After 
dilution  with  much  water,  it  should  not  give  any  precipitate 
with  nitrate  of  silver  (indicating  chlorine)  or  with  nitrate  of 
baryta  (indicating  sulphuric  acid).     Excess  of  ammonia  (5) 
followed  by  sulphide  of  ammonium  should  not  produce  any 
change  in  it. 

Dilute  nitric  acid  may  be  made  by  mixing  the  strong  acid 
with  twice  its  volume  of  distilled  or  rain  water. 

346.  NITROPRUSSIDE  OP  SODIUM,  Na2FeNOCy5,  may 
be  procured  in  red  crystals  from  the  operative  chemist.     It  is 
an  expensive  salt,  very  rarely  required.    A  solution  of  it  may 
be  obtained  by  boiling  ferrocyanide  of  potassium  with  diluted 
nitric  acid  till  it  ceases  to  give  a  blue  precipitate  with  sulphate 
of  iron,  then  adding  an  excess  of  carbonate  of  soda,  boiling, 
and  filtering.     The  solution  should  give  a  fine  purple  blue 
color  with  sulphide  of  ammonium. 

347.  OXALATE    OF    AMMONIA,  Or  AMMONIC    OxALATE, 

(NH4)2C2O4,  is  sold  by  the  operative  chemist  in  crystals  (75). 
Two  drachms  of  the  salt  should  be  dissolved  in  six  measured 
ounces  of  distilled  or  rain  water. 

348.  PERCHLORIDE  OF   IRON,  or  FERRIC   CHLORIDE, 


238  TESTS    USED    IN    ANALYSIS. 

FeaC]6,  is  also  called  sesq  Bichloride  of  iron  and  mttriate  of 
iron.  It  is  obtained  from  the  operative  chemist  in  the  state 
of  solution  in  water  (45). 

It  may  be  prepared  by  dissolving  iron  (wire,  nails,  or 
filings)  with  the  aid  of  heat,  in  a  mixture  of  dilute  hydro- 
chloric acid  with  one-fourth  of  dilute  nitric  acid,  evaporating 
at  a  moderate  heat  till  the  liquid  is  syrupy,  and  diluting 
with  water. 

Perchloride  of  Iron  is  a  test  for 

Ferrocyariides       ....  Dark-blue  precipitate  (77) 

Su.phoc^Udes   .     .     .     . 


Tannic  acid  )         .     .     .     .       \    Inky-black     precipitate    or    color 

Gallic  acid    )        .     .     .     .      (        (152,  153) 

Hyposulphites     ....-[    Resolution,  soon  becoming  color- 

349.  PERCHLORIDE  OF  MERCURY,  or  MERCURIC  CHLO- 
RIDE, HgCl2,  is  sold  by  the  druggist  in  the  solid  form,  as 
bichloride  of  mercury  or  corrosive  sublimate  (31). 

Two  drachms  of  the  salt  may  be  dissolved  in  four  meas- 
ured ounces  of  water. 


Perchloride  of  Mercury  is  a  test  f 


or 


Tin  as  a  stannous  compound      )    ,,,,  ., 

or  protosalt     ....      }    Whlte 
Iodides      .......  Scarlet  precipitate  (93). 

349a.  PERMANGANATE  OF  POTASH,  K2Mn2O8,  is  sold  in 
solution  as  Condy's  disinfecting  fluid.  The  crystallized  salt 
may  be  obtained  from  the  operative  chemist.  Twenty  grains 
of  the  salt  may  be  dissolved  in  four  ounces  of  water. 

350.  PHOSPHATE  OF  SODA,  or  HYDRO-DISODIC  PHOS- 
PHATE, Na2HPO4,  may  be  obtained,  in  crystals,  from  the 
druggist  (80).     Half  an  ounce  of  the  salt  may  be  dissolved 
in  ten  measured  ounces  of  distilled  or  rain  water. 

351.  POTASH,  or  POTASSIC  HYDRATE,  KHO,  is  sold  by 
the  druggist  both  in  solution  as  liquor  potasses,  and  in  the 
solid  form  as  potassa  fusa  in  sticks  (77).    About  eight  ounces 
of  the  solution  should  be  provided.     One  ounce  of  the  solid 


TESTS    USED    IN    ANALYSIS.  239 

potash  maybe  dissolved  in  eight  measured  ounces  of  distilled 
or  rain  water. 

The  solution  of  potash  should  not  effervesce  strongly  on 
adding  an  excess  of  hydrochloric  acid  (indicating  carbonic 
acid). 

The  acidified  solution  should  give  but  a  slight  flocculent 
precipitate  (alumina)  on  adding  ammonia  in  excess.  Hydro- 
sulphate  of  ammonia  added  to  this  solution  should  give  little, 
if  any,  dark  tinge  (indicating  iron,  lead,  or  copper). 

Potash  is  a  test  for 
Mercury,  as  a  mercuric  salt  .        Yellow  precipitate  (31) 

(    Blue  precipitate,  becoming  black 
Copper <        when  boiled  with  excess  of  pot- 


ash (27) 

Iron,  as  a  ferric  compound,  or  j  Red_brown  precipitate  (45) 

persalt j 

Iron,  as  a  ferrous   compound,    f   Dark  green  precipitate,  becoming 

or  protosalt (       brown  when  exposed  to  air  (45) 

f   Wh  ite  precipitate,  becoming  brown 

I       when  shaken  with  air  (55) 

(   Pale  green  precipitate,  insoluble 

^lcke {       in  excess  (49) 

Cobalt Blue-  precipitate  (47) 

C   Green  precipitate,  soluble  in  excess 

Chromium <        to  a  green  solution,  precipitated 

(       by  boiling  (61) 
Ammonia Odor  of  ammonia  on  boiling  (75) 

352.  PROTOCHLORIDE  OF  TIN,  or  STANNOUS  CHLORIDE, 
SnCl2,  should  be  prepared  by  boiling  two  drachms  of  tin 
with  half  a  measured  ounce  of  strong  hydrochloric  acid. 

The  solution  may  be  diluted  with  two  ounces  of  water,  and 
some  metallic  tin  should  be  kept  in  it,  to  prevent  it  from 
becoming  converted  into  stannic  chloride  by  the  combina- 
tion of  a  portion  of  its  tin  with  atmospheric  oxygen. 

Tin  is  sold  by  the  operative  chemist  in  the  granulated 
state,  which  is  easily  dissolved  by  hydrochloric  acid. 

Tin-foil  often  contains  lead.  If  this  metal  be  present  in 
the  solution  of  protochloride  of  tin,  it  will  give  a  precipitate 
with  dilute  sulphuric  acid. 


240  TESTS     USED    IN    ANALYSIS. 

Frotochloride  of  Tin  is  a  test  for 

Gold Purple-brown  precipitate 

Platinum Bright  red  solution 

Mercury Gray  precipitate  (31). 

353.  STARCH,  C6H]0O5 — A  drachm. of  white  starch  is 
rubbed   down   in  a  mortar  with  a  measured  ounce  of  cold 
water.     The  mixture  is  poured  by  degrees  into  five  ounces 
of  boiling  water  in  a  dish. 

Starch  is  a  test  for 
Free  iodine .     Blue  color  (93). 

354.  SULPHATE  OF    COPPER,  or  CUPRIC    SULPHATE, 
CuSO4,  is  sold   at  the   oil-shops  as  blue  copperas  or  blue 
vitriol,  in  crystals  (27).     Half  an  ounce  of  the  salt  may  be 
dissolved  in  five  ounces  of  water. 

355.  SULPHATE    OF    IRON,   or   FERROUS    SULPHATE, 
FeSO4,  also  called  protosulphate  of  iron,  is  sold  at  the  oil- 
shops  in  crystals  under  the  name  of  copperas  or  green  vitriol, 
(45).     One    ounce  of  the    salt    may   be    dissolved  in  four 
measured  ounces  of  cold  distilled  or  rain  water. 

356.  SULPHATE  OF  LIME,  or  CALCIC  SULPHATE,  CaS04, 
is  sold  at  the  oil-shops  as  plaster  of  Paris  (69).     About  a 
drachm  of  the  powder  may  be  heated  with  half  a  pint  of 
water  for  some  minutes,  with  occasional  stirring,  allowed  to 
stand  till  cold,  and  filtered  off. 

357.  SULPHATE    OF    MAGNESIA,   or   MAGNESIC    SUL- 
PHATE, MgSO4,  is  obtained  from   the   druggist  as  Epsom 
salts  (9).     One  ounce  of  the  salt  may  be  dissolved  in  five  or 
six  measured  ounces  of  water. 

358.  SULPHATE  OF  MANGANESE,  or  MANGANOUS  SUL- 
PHATE, MnSO4,  may  be  obtained  in  crystals  from  the  opera- 
tive chemist  (55).     One  drachm  of  the  salt  may  be  dissolved 
in  two  ounces  of  water. 

Sulphate  of  Manganese  is  a  test  for 
Hypochlorites      ....     Dark-brown  precipitate  (91). 


TESTS     USED    IN    ANALYSIS.  241 

SULPHIDE  OF  AMMONIUM;  see  HYDROSULPHATE  OF 
AMMONIA. 

359.  SULPHURIC  ACID,  H2SO4,  is  sold  at  the  oil-shops  as 
oil  of  vitriol,  which  is  often  of  a  dark  brown  color,  and  unfit 
for  use  in  analysis.     By  carefully  boiling  it  in  a  flask  it  may 
be  rendered  nearly  colorless,  the  organic  matter  to  which 
the  brown  color  is  due  being  oxidized  by  one  portion  of  the 
acid.    The  flask  must  be  allowed  to  cool  before  attempting  to 
pour  out  the  acid. 

It  is  advisable,  if  possible,  to  obtain  the  nearly  colorless 
oil  of  vitriol  from  the  druggist.  It  must  be  kept  in  a  stop- 
pered bottle. 

Dilute  Sulphuric  Acid  is  made  by  pouring  one  measured 
ounce  of  oil  of  vitriol,  slowly,  with  continual  stirring,  into 
four  measured  ounces  of  water  in  an  evaporating  basin, 
beaker  or  flask  (not  in  a  measure  or  bottle).  The  mixture  is 
allowed  to  cool,  and  the  clear  diluted  acid  poured  off  from  the 
sulphate  of  lead  which  is  usually  deposited  from  the  common 

acid. 

Strong  Sulphuric  Acid  is  a  test  for 

I      Red  color,  and  evolution  of  yellow 
Chlorates  .     .     .     .      j          explosive  gas  (90) 
Iodine Violet  vapors  on  heating  (93). 

360.  TARTARIC  ACID,  C4H6O6,  is  sold  in  crystals  by  the 
druggist  (158),    One  ounce  may  be  dissolved  in  four  measured 
ounces  of  water. 

361.  TURMERIC  PAPER  may  be  obtained  from  the  opera- 
tive chemist.     Its  yellow  color  soon  fades  in  a  strong  light. 

To  prepare  turmeric  paper,  gently  heat  one  drachm  of 
powdered  turmeric  (the  root  of  Curcuma  longa]  in  six  meas- 
ured drachms  of  methylated  spirit,  till  the  solution  has  a 
bright  yellow  color.  Filter  it,  and  dip  white  filter-paper  or 
unsized  drawing-paper  into  it.  Hang  the  paper  on  a  string 
to  dry. 

362.  WATER If  it    can    be    procured,  distilled  water 

only  should  be  employed  in  analytical  operations.     It  should 

91 


242  TESTS    USED    IN    ANALYSIS. 

be  tested  in  the  following  manner,  each  test  being  performed 
upon  a  separate  portion  : — 

1.  Evaporate  a  few  drops  upon  a  slip  of  glass ;  scarcely  a 

trace  of  solid  matter  should  remain. 

2.  Add  Nitrate  of  Silver  ;  no  turbidity  (indicating  chlo- 

rides or  hydrochloric  acid)  should  be  produced. 

3.  Add  Chloride  of  Barium  ;  there  should  be  no  turbidity 

(indicating  sulphates). 

4.  Add  Oxalate  of  Ammonia  ;  there  should  be  no  turbidity 

(indicating  lime). 

5.  Add  Hydrosulphuric  Acid  ;  there  should  be  no  dark 

tinge  (indicating  lead  or  copper). 

Rain-water,  after  being  filtered,  may  often  be  substituted 
for  distilled  water. 

Should  neither  distilled  nor  rain  water  be  procurable,  the 
analyst  should  test  the  common  water  as  directed  above,  and 
make  a  careful  note  of  the  results,  to  be  subsequently  em- 
ployed in  correcting  his  analysis. 

Common  water  may  often  be  in  great  measure  deprived 
of  the  lime  and  magnesia  which  it  contains,  by  boiling  it 
gently  in  a  kettle  for  half  an  hour,  allowing  it  to  cool,  and 
filtering  from  the  deposited  carbonates  of  lime  and  magnesia. 

Any  of  the  arrangements  represented  at  pp.  168—171  may 
be  employed  for  distilling  water. 

363.  ZINC  may  be  procured  at  the  ironmonger's.  Thin 
sheet  zinc  cut  up  into  strips  will  be  found  very  convenient. 

The  operative  chemist  furnishes  granulated  zinc,  made  by 
melting  the  metal  in  an  iron  ladle  or  earthern  crucible,  and 
pouring  it,  in  a  thin  stream,  into  a  pail  of  water,  from  a 
height  of  eight  or  ten  feet. 


APPARATUS. 


243 


APPARATUS  REQUIRED  FOR  THE  QUALITATIVE  ANALYSIS 
OF  SINGLE  SUBSTANCES. 

364.  The  following  list  includes  the  principal  articles 
which  are  necessary  for  the  identification  of  single  sub- 
stances. 

They  may  be  provided  for  ten  or  twelve  shillings. 


12  test  tubes 

Rack  with,  draining  pegs 

Tube-cleaner 

Spirit  lamp  or  gas  burner 

3  funnels  :  2  oz.,  1  oz.,  ±  oz. 

Filter-paper 

Slips  of  window-glass 

Glass-rod 


Narrow  hard  glass  tubing 

Blowpipe 

Triangular  file 

Platinum  wire  and  foil 

4  oz.  evaporating  dish 

Half-pint  Wedgwood  mortar 

Wire  triangle 

Wire  tripod  or  retort-stand. 


244 


APPENDIX. 


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INDEX. 


A  CETATE     of     ammonia    pre- 
1\.  pared,  64 

of  copper,  37 

of  lead,  Pb(C.,H302)2,  29 

for  testing,  228 
Acetates,  action  of  heat  on,  133 

common,  133 

Acetic  acid,  HC.2H302,  133 
confirmed,  133 
detected,  129 
for  testing,  228 
identified,  133 

ether.  133 
Acetone,  132 

identified,  163 
Acid  reaction,  34 

vapors,  221 
Acids  detected,  91 
Acroleine,  156 
Agate  mortar,  119 
Albumen,  154 

soluble,  identified,  154 
Alcohol,  extracted,  167 

for  testing,  228 

identified,  162 

separated  from  water,  167 
Aldehyde  identified,  163 
Alkali  waste,  100 
Alkaline  reaction,  34 
Alkaloids,  general  test  for,  179 

identified,  144 
Alum,  59 

chrome,  67 

concentrated,  59 
Alumina,  acetate,  60 

hydrate,  58 

phosphate,  109 

silicate,  59,  127 

sulphate,  59 
Aluminate  of  soda,  60 
Aluminium  and  sodium,  fluoride, 
97 


Aluminium  blowpipe  test,  190 

common  compounds  of,  59 

confirmed,  58 

detected,  51 

identified,  58 
Ammonia,  NH3,  79 

acetate,  134 

prepared,  64 

alum,  59 

carbonate  (NH4)2C03,  80 

common  compounds  of,  79 

detection,  77 

for  testing,  228 

hydrochlorate,  NH4C1,  79 

hydrosulphate  (NH4HS),  80 

identification,  79 

in  excess,  21 

molybdate,  236 
f  muriate,  79 
"  nitrate,  80 

oxalate  (NH4)2C204,  80 

sesquicarbonate,  80 

solution,  79 

sulphate,  80 

test  for,  239 

urate,  142 

Ammonic  carbonate,  (NH<)2C03, 
80 

chloride  NH4C1,  79 

oxalate,  (NH4)2C204,  80 

sesquicarbonate,  80 

sulphide,  (NH4)2S,  80 
Ammoiiio-hydric  sulphide,  233 
Ammonium,  79 

blowpipe  test,  190,  201 

chloride,  NH4C1,  79 

common  compounds  of,  79 

sulphide  (NH4),S,  80 
Amorphous  phosphorus,  108 
Analysis  by  blowpipe,  190 

liquid  tests,  17 
Anglesite  (sulphate  of  lead),  30 


246 


INDEX. 


Aniline  identified,  164 
oxalate,  164 
purple,  164 
red,  164 

Animal  charcoal,  123 
Antimoniate  of  potash,  KSb03,  50 
Antimonic  acid,  126 
Antimony    and    arsenic    distin- 
guished, 44 
blowpipe  test,  201 
chloride,  50 

common  compounds  of,  49 
confirmed,  48 
crude,  49 
detected,  32 
flowers  of,  49 
gray  ore  of,  49 
identified,  48 

in  insoluble  substances,  126 
•     oxide,  49 

potassio-tartrate,  49 
sulphide,  49 
sulphuret,  49 

blowpipe  test,  202 
terchloride,  50 
teroxide,  49 
tersulphide,  49 
test  for,  235 
vermilion,  49 
Apparatus,  243 
Aquafortis,  106 
Argand  burner,  94 
Argentic  nitrate,  236 
Argol,  84 

Arseniate  of  soda,  46 
Arsenic  acid,  46 

and  antimony  distinguished, 

44 

bisulphide,  46 
blowpipe  test,  190,  199 
common  compounds  of,  45 
confirmed,  42 
detected,  32 

expelled  by  roasting,  203 
identified,  45 
in  ores,  202 
iodide,  46 
sulphide,  46 
tersulphide,  46 
white,  45 

Arsenietted  hydrogen,  44 
Arsenious  acid,  45 

crystals,  42 


Arsenious  acid  detected,  32 

identified,  45 

reduced,  200 
Arsenite  of  copper,  37,  45 
Astringent  substances,  186 
Aurum  musivum,  47 

BANDAGE,  caoutchouc,  168 
Baric  chloride,  BaCl2,  231 

nitrate,  Ba(N03)2,  236 
Barium,  69 

blowpipe  test,  212 

carbonate,  69 

chlorate,  70 

chloride,  BaCl2,  70 

chromate,  70 

common  compounds  of,  69 

confirmed,  69 

detected,  68 

nitrate,  Ba(N03)2,  70 

sulphate,  69,  125 
Baryta,  70 

blowpipe  test,  212 

carbonate,  69 

chlorate,  70 

chromate,  70 

confirmed,  69 

detected,  68 

hydrate,  70 

nitrate,  Ba(N03)2,  70 

oxalate,  111 

sulphate,  69,  125 

blowpipe  test,  212 
Barytes,  125 

muriate,  70 

Bases,  organic,  identified,  144 
Bending  tubes,  172 
Benzoic  acid,  detected,  130 

identified,  136 
Benzine,  166 
Benzole,  166 
Benzonitrile,  136 
Biborate  of  soda,  Na20,2B203,  89 
Bicarbonate  of  soda,  NaHC03,  87 

for  testing,  229 

Bichloride  of  mercury  for  testing, 
HgCl2,  229 

of   platinum   for    testing, 

PtCl4,  229 
Bichromate  of  potash,  67  • 

for  testing,  229 
Bismuth,  blowpipe  test,  202 
citrate,  140 


INDEX. 


247 


Bismuth,  common  compounds  of, 

39 

confirmed,  38 
detected,  32 
identified,  39 
nitrate,  39 
oxide,  39 
oxychloride,  39 
tested  for  silver,  206 
trisnitrate,  39 
Bisulphate  of  potash  for  testing, 

KHS04,  230 
in   blowpipe   analysis, 

218 

test,  217 
Bisulphide  of  carbon  identified, 

167 
Bitter  almond  oil,  166 

almonds,  odor  of,  137,  166 
Black  borax  bead,  209 
jack,  61 
lead,  123 

oxide  of  copper,  38 
of  iron,  55 
of  manganese,  63 
sulphide  of  antimony,  49 
Bleaching  powder,  74 
Blende,  61 
Blowpipe  analysis,  190 

borax  bead  test,  194 
cobalt  test,  196 
colored  flame  test,  195 
detection  of  acids,  216 
for  non-metals,  216 
for  reduction   on  char- 
coal, 191 

detection  of  ammonium,  ar- 
senic, mercury,  197 
gas,  173 

reduction  of  metals  by,  191 
spirit,  173 

test  in  small  tubes,  221 
Blue  carbonate  of  copper,  37 
crystals,  37 
flame,  81 
fused  mass,  124 
indigo,  149 
iodized  starch,  155 
litmus  paper,  235 
mass,  with  nitrate  of  cobalt, 

198 

Prussian,  56,  111 
smalt,  57 


Blue  solution,  37,  57 
•     stone,  37 

Turnbull's,  52 

ultramarine,  100 

vitriol,  37 
Boiling,  19 
Bone-ash,  64 

for  cupellation,  230 
Bone-black,  123 
Boracic  acid,  blowpipe  test,  226 
confirmed,  112 
crystals,  113 
detected,  93 
for  testing,  230 
identified,  113 
Tuscan,  113 
Borate  of  lime,  113 
Borates,  blowpipe  test,  226 

detected,  93 

on  charcoal,  193 
Borax,  Na./).2B203,  89 

bead  test,  194 

beads,  208 

blowpipe  test,  226 

for  testing,  230 
Boron,  fluoride,  226 
Boronatrocalcite,  113 
Brass,  204 
Brick,  127 
Brimstone,  122 
British  gum,  155 
Bromides,  blowpipe  test,  220 
Bromine  detected,  96,  103 
Bronze  powder,  47 
Brown  acid  vapors,  221 

caramel,  149 

chromate  of  lead,  30 

color  with  potash,  154 

ferrocyanide  of  copper,  111 

haematite,  54 

oxide  of  lead,  29 

residue    with   nitric   acid, 
29 

vapors,  103 
Brucine  detected,  144 

identified,  146 
Brunswick  green,  38 
Bullets,  shrapnel,  205 
Bunsen's  burner,  75,  95 
Burnett's  disinfecting  fluid,  62 
Burnt  sugar  odor,  137 
Butyric  acid  identified,  163 

ether,  164 


248 


INDEX. 


CADMIUM,  test  for,  235 
Caffeine  detected,  145 
Caffeine  identified,  145 
Calamine,  til 

electric,  128 

Calcic  chloride,  CaCl2,  74 
sulphate,  CaS04,  73 
Calcined  magnesia,  24 
Calcium,  71 

blowpipe  test,  212 
carbonate,  72 
chloride,  CaCl2,  74 
common  compounds  of,  72 
detected,  68 
fluoride,  65 

blowpipe  test,  214,  219 
oxalate,  74 
phosphate,  64 

blowpipe  test,  213 
sulphate,  CaS04,  73 

blowpipe  test,  213 
sulphide,  100 
Calomel,  27 

Cane  sugar  identified,  152 
Caoutchouc  bandage,  168 
Caramel  identified,  149 
Carbazotic  acid  identified,  149 
Carbolic  acid,  164 

identified,  150 
Carbon,  122 

identified,  116 
Carbonate  of   ammonia, 

(NH4)2C03,  80 
for  testing,  230 
precipitate,  68 
copper,  37 
lead,  29 
lime,  72 
magnesia,  24 
soda,  Na2C03,  87 
bead,  209 
for  testing,  230 
Carbonates,  blowpipe  test,  217 

common,  99 
Carbonic  acid,  detected,  91 

identified,  99 
oxide,  identified,  111 
Carbonization  by  heat,  96 
Carmine  flame,  212 
Caseine,  159 
Cast-iron  identified,  53 
Caustic,  26 
potash,  83 


Caustic  soda,  88 
Cawk,  125 
Celestine,  71,  125 
Ceroleine,  159 
Cerotic  acid,  159 
Cetine,  159 
Chalcedony,  126 
Chalk,  73 
Char,  123 
Charcoal,  animal,  123 

blowpipe,  191 

wood,  123 
Chili  saltpetre,  88 
Chloral,  hydrate,  150 
Chlorate  of  baiyta,  70 

potash,  82 

blowpipe  test,  220,  222 
Chlorates,  common,  98 

on  charcoal,  194 

test  for,  241 
Chloric  acid,  98 

detected,  91 
Chloric  peroxide,  97 
Chloride,  mercurous,  27 

of  ammonium,  NH+C1,  79 
for  testing,  231 
use  in  analysis,  23 

of  barium  for  testing,  BaCL, 
231 

of  calcium  for  testing,  CaCL. 
231 

of  lead,  30 

of  lime,  74 

for  testing,  231 

of  mercury,  HgCl2,  27,  41 

of  silver,  26 

of  tin,  36 
Chlorides  detected,  91 

by  blowpipe,  218 

impurities,  103 

test  for,  237 
Chlorine  confirmed,  103 

detected,  91 

evolved,  29,  63 

preparation,  232 

water,  for  testing,  232 
Chloroform,  identified,  165 

tested,  165 
Chloropicrine,  149 
Cholesterine  identified,  157 
Chromate  of  lead,  29 

of  potash,  K2Cr04,  67 
Chromates  detected,  92 


INDEX. 


249 


Chrome  alum,  67 

iron  ore,  66 

orange,  29 

yellow,  29 
Chromic  acid,  114 

detected,  92 

identified,  114 

test  for,  228 
Chromium,  66 

blowpipe  test  for,  209 

common  compounds  of,  66 

confirmed,  66 

by  blowpipe,  209 

detected,  51 

insoluble  compounds,  128 

oxide,  66 

test  for,  239 

Cinchonine  detected,  144 
in  quinine,  147 

identified,  148 

sulphate,  148 
Cinnabar,  41 
Citrates,  common,  140 
Citric  acid  detected,  130 

identified,  139 
Classification  of  metals,  18 
Clay,  59,  127 
Cleavage,  31 
Coal  identified,  123 
Coal-tar  odor,  148 
Cobalt,  57 

blowpipe  test,  209 

confirmed,  57 

detected,  51 

glance,  57 

metallic,  57 

nitrate,  Co(N03)2,  57 

ores,  209 

oxide,  57 

test  for,  239 

test   in    blowpipe   analysis, 

196 

Cobaltous  nitrate,  236 
Coke  identified,  123 
Colcothar,  55 
Colored  beads,  208 

flames,  212 

flame  test,  74 
Common  salt,  88 
Concentrated     sulphuric     acid, 

H2S04,  241 
Condenser,  168 
Condy's  disinfectant,  63 


Copper,  36 

acetate,  37 

alloys,  204 

arsenite,  37,  45 

blowpipe  test,  210,  212 

carbonate,  37 

common  compounds  of,  37 

confirmed,  36 

detected,  32 

detected  in  lead,  206 

detection  by  blowpipe,  203 

ferrocyanide,  111 

glance,  38 

identified,  36 

metals  precipitated  by,  232 

ore,  gray,  204 

oxide,  38 

oxy chloride,  38 

pyrites,  203 

suboxide,  38 

sulphate,  CuS04,  37 

sulphide,  38 

test  for,  229,  233 

test  for  nitric  acid,  105 
Copperas,  55 
Cork  borers,  171 
Corks  fitted,  172 

perforated,  171 
Corrosive  sublimate,  31 
Coughing  indicates  succinic  acid, 

132 

Cream  of  tartar,  S3 
Crimson  flame,  71 
Crocus,  55 
Crucible  tongs,  117 
Crushing-mortar,  120 
Cryolite,  9"J 

Crystals  formed  on  cooling,  30 
Cupellation,  205 
Cupric  oxide,  38 

sulphate,  CuS04,  240 
Cuprous  oxide,  38 

sulphide,  38 
Cyanide  of  mercury,  41 
analysis,  101 

potassium,  commercial, 

KCN,  84 

for  testing,  232 
in  blowpipe  analysis, 207 
Cyanides,  common,  101 

detected,  93 
Cyanogen,  222 

detected,  93 


250 


INDEX. 


DECANTATION,  33 
Decrepitation,  30,  41,  65 
Deflagration,  82 
Deliquescence,  62,  74,  82 
Dextrine  identified,  155 
Diamond,  122 

mortar,  120 

Dilute  hydrochloric  acid  for  test- 
ing, 233 

nitric  acid  for  testing,  237 
Dilute  sulphuric  acid  for  testing, 

240 

Dinas  fire-brick,  127 
Dish,  evaporating,  94 
Disinfectant,  Burnett's,  62 

Condy's,  63 
Dissolving,  19 
Distillate,  169 
Distillation,  168 
Distilled  water,  241 
Dolomite,  73 
Dropping-tube,  196 

Tf  ARTHENW'ARE,  127 

JL     Effervescence,  91 
Efflorescence,  87 
Electric  calamine,  128 
Emery,  59 
Emulsion,  156 
Epsom  salts,  24 
Essence  of  mirbane,  166 
Ether,  caution  in  using,  158 

for  testing,  232 

identified,  165 
Evaporating  dish,  94 
Evaporation,  94 

on  glass,  20 

on  water-bath,  174 
Excess,  meaning  of,  21 
Explosion  with  sulphuric  acid, 
97 

FERRIC  acetate,  134 
chloride,  Fe,Cl6,  56 
citrate,  140 
oxide,  54 

salts  detected,  52 
Ferridcyanide      of      potassium, 

K3FeCy6,  84 

potassium,  for  testing,  232 
Ferridcyanides  detected,  100 
Ferrocyanide  of  calcium  and  po- 
tassium, 111 


Ferrocyanide  of  potassium,  K4Fe 

Cy6,  84 

Ferrocyanides  detected,  110 

test  for,  238 
Ferrocyanogen,  110 
Ferrous  carbonate,  56 

iodide,  56 

oxide,  52 

salts  detected,  52 
Ferrous  sulphate,  FeS04,  55 

sulphide,  55 
Fibrous  gypsum,  73 
File,  rat's-tail,  171 
Filters,  20 
Filtration,  20 
Fire-brick,  127 
Fire-clay,  127 
Flake  white,  39 
Flame,  colored,  test  by,  74 
Flask  for  distillation,  170 
Flint,  126 
Fluorescence,  147 
Fluoric  acid,  97 
Fluoride  of  calcium,  65 
Fluorides,  blowpipe  test,  219 

detected,  91 
Fluorine,  97 

confirmed,  96 

detected,  91 
Fluor-spar,  65 

blowpipe  test,  2]  4 
Focus  of  blowpipe-flame,  203 
Formic  acid  detected,  130 

identified,  134 
French  chalk,  128 
Frosted  silver,  206 
Fructose,  153 
Fruit-sugar,  153 
Fuller's  earth,  127 
Fulminate  of  mercury,  101 
Fumaric  acid,  141 
Fumes,  cause  of,  96 
Fuming  sulphuric  acid,  102 
Funnel-tube,  170 
Fusing-point  determined,  157 
Fusion  of  insoluble  substances, 
120 

pALENA,  30 

VI     Gallic  acid  detected,  130 

identified,  135 

test  for,  238 
Garlic  odor  of  arsenic,  45 


INDEX. 


251 


Gas  blowpipe,  173 

Gas-burners,  94 

Gas -carbon  identified,  123 

Gauze-burner,  95 

Gelatine  identified,  155 

German  tubing,  33 

Glacial  phosphoric  acid,  107 

Glance  cobalt,  57 

Glass  jet,  43 

of  borax,  90 

of  metaphosphate  of  soda, 
108 

rod,  22 

soluble,  90 

tubes  bent,  172 

with     carbonate    of    soda, 

224 

Glauber's  salt,  88 
Glucose  identified,  152 
Glycerin  identified,  174 
Gold,  Mosaic,  47 

test  for,  240 
Goulard's  extract,  133 
Granulated  zinc,  242 
Grape-sugar  identified,  152 
Graphite,  123 
Green  acetate  of  copper,  37 

Brunswick,  38 

carbonate  of  copper,  37 

flame,  109,  212 

fused  mass,  124 

nitric  acid,  106 

oxide  of  chromium,  66 

Scheele's,  37,  45 

solution,    36,    58,    64,    67, 
84 

vitriol,  55 
Gray  antimony  ore,  49 

copper  ore,  204 
Grough  saltpetre,  82 
Gum  identified,  155 

British,  155 
Gun-metal,  204 
Gunpowder,  analysis  of,  244 
Gypsum,  73 

blowpipe  test,  213 

HAEMATITE,  54 
Hartshorn,  79 
Heating  solids  in  air,  117 
in  bent  tube,  118 
in  tubes,  33 
on  platinum  foil,  117 


Heavy  spar,  69,  125 

blowpipe  test,  213 
Hippuric  acid  detected,  130 

identified,  136 
Hydriodate  of  potash,  85 
Hydriodic  acid  detected,  92 

test  for,  237 

Hydrobromic  acid  detected,  96 
Hydrochloric  acid,  HC1,  104 

detected,  91 

for  testing,  233 

identified,  104 

precipitate,  25 

test  for,  237 

Hydrocyanic     acid     confirmed, 
100 

detected,  93 

identified,  101 

Hydrodisodic  phosphate,  238 
Hydroferrocyanic  acid  identified, 

110 
Hydrofluoric  acid  detected,  91 

identified,  97 
Hydrofluosilicic  acid  for  testing, 

2HF.SiF4,  233 
Hydrogen  prepared,  43 

tested,  43 
Hydropotassic     metantirnoniate, 

229 

•  sulphate,  230 
Hydrosodic  carbonate,  87 

for  testing,  229 

Hydrosulphate    of    ammonia, 
NH4HS,  80,  233 

precipitate,  51 

yellow,  80 

Hydrosulphocyanic  acid,  101 
Hydrosulphuric  acid,  H2S,  233 

apparatus,  234 

confirmed,  99 

detected,  91 

for  testing,  233 

identified,  99 

in  excess,  21 

precipitate,  32 

prepared,  234 

test  for,  228 

Hypochlorite  of  lime,  74 
Hypochlorites,  test /or,  240 
Hypochlorous  acid  confirmed,  98 

detected,  93 

Hyposulphite  of  soda,  89 
Hyposulphites  detected,  91 


252 


INDEX. 


ICELAND  SPAR,  73 
1     Impalpable  powder,  120 
Incandescence,  208 
Incense,  odor  of,  132 
Incrustation  on  charcoal,  192 
Indigo,  action  of  heat  on,  149 

identified,  149 

reduced,  149 
Ink  identified,  135 
Insoluble   substances   analyzed, 

116 
Iodide  of  arsenic,  46 

of  lead,  30 

of  mercury,  41 

of  potassium  for  testing,  KI, 

235 
Iodides,  blowpipe  test,  217 

common,  99 

detected,  91 

test  for,  237 
Iodine  confirmed,  98 

detected,  91 

for  testing,  235 

free  test  for,  240 

identified,  98 

by  blowpipe,  221 

vapor,  221 

water,  235 
Iron  acetate,  134 

ammonio-citrate,  140 

and  quinine  citrate,  140 

as  an  impurity,  210 

bisulphide,  55 

black  oxide,  55 

blowpipe  test,  208 

carbonate,  56 

cast,  identified,  53 

citrate,  140 

common  compounds  of,  54 

confirmed,  52 

detected,  51 

by  blowpipe,  208 

ferrocyanide,  56,  111 

identified,  52 

iodide,  56 

magnetic  oxide,  55 

muriate,  56 

perchloride,  Fe2Cl6,  56 

peroxide,  54 

phosphate,  109 

protosulphate,  FeS04,  55 

pyrites,  55 

sesquichloride,  Fe2Cl6,  56 


Iron,  sesquioxide,  54 

silicate,  56 

slag,  56 

spathic  ore  of,  56 

specular,  54 

sulphate,  FeS04,  55 

action  of  heat  on,  210 

sulphide,  55 

sulphuret,  55 

tannate,  135 

test  for,  52,  229,  233 

tinned.  207 

wire  for  blowpipe  analysis, 
226 

wrought,  identified,  53 
Ivory  black,  123 

JET  for  burning  gases.  43 
Joints  for  apparatus,  168 

KAOLIN,  127 
Kaolinite,  127 
Kryolite,  97 

identified,  97 

T  ACTIC  acid  identified,  174 
L     Lactide,  174 
Lactine  identified,  153 
Lamp-black  identified,  123 
Lamps,  94 
Lead,  28,  204 

acetate,  PhCC-J^O.^,  29 
for  testing,  228 

alloys,  205 

binoxide,  29 

blowpipe  test,  201 

carbonate,  29 

chloride,  30 

chromate,  29 

common  compounds  of,  28 

confirmed,  27 

detected,  25,  32 

extracted  from  galena,  204 

identified,  28 

iodide,  30 

nitrate,  30 

ore,  204 

oxide,  28 

oxychloride,  30 

peroxide,  29 

phosphate,  110 

precipitated     by    sulphuric 
acid,  27 


INDEX. 


253 


Lead,  red  oxide,  29 

sugar  of,  29 

sulphate,  30 

sulphide,  30 

sulphide  in  blowpipe  analy- 
sis, 204 

tartrate,  138 

test  for,  235 

tested  for  copper,  206 

tested  for  silver,  205 

tribasic  acetate,  133 

white,  29 

Lemons,  essential  salt  of,  85 
Levigatioii  in  blowpipe  analysis, 

193 

Liebig's  condenser,  168 
Lime,  CaO,  72 

blowpipe  test,  212 

borate,  113 

carbonate,  72 

chloride,  74 

citrate,  141 

detected,  68 

hydrate,  CaO.H20,  72 

hypochlorite,  74 

oxalate,  65,  74 

phosphate,  64 

blowpipe  test.  226 
detected,  51 

slaked,  72 

sulphate,  CaS04,  73 
blowpipe  test,  213 

superphosphate,  64 

tartrate,  137 

water,  CaO.H20,  72 
Limestone,  73 
Liquids,    unknown,    examined, 

181 

Liquor  ammonice,  79 
Liquor  potassfe,  83 
Litharge,  28 
Lithates,  142 
Lithic  acid  identified,  141 
Lunar  caustic,  26 

MAGNESIA,  24 
ammonia  phosphate,  65 
basic  carbonate,  24 
calcined,  24 
carbonate,  24 
citrate,  141 

granulated,  141 
common  compounds  of,  23 


Magnesia  detected,  17 

phosphate,  65 

precipitated  by  ammonia,  23 

silicate,  128 

sulphate,  MgS04,  24 
Magiiesian  limestone,  73 
Magnesia  sulphate,  24,  240 
Magnesite,  24 
Magnesium  blowpipe  test,  190 

common  compounds  of,  23 

detected,  17 

identified,  23 
Malachite,  37 
Malseic  acid,  141 
Mallic  acid  detected,  130 

identified,  141 
Malleability  tested,  "192 
Manganate  of  potash,  64 

Manganese,  62 

binoxide,  Mn02,  63 

black,  63 

blowpipe  test,  208 

common  compounds  of,  63 

confirmed,  62 

by  blowpipe,  209 

detected,  51 

ore,  63 

oxide,  63 

sulphate,  MnS04,  63 
•   test  for,  239 

Manganous  sulphate,  63,  240 
Marble,  73 

Marsh's  test  for  arsenic,  42 
Massicot,  28 

M.B.  examination,  organic  sub- 
stances for,  183 
Meconic  acid  detected,  130 

identified,  135 
;  Meerschaum,  128 
Melting-point  determined,  157 
Mercuric  chloride,  HgCl2,  41,  238 

compounds,  40 

cyanide,  41 

iodide,  41 

oxide,  41 

sulphide,  41 
Mercurous  chloride,  27 

compounds,  27 

nitrate,  27 
Mercury,  27 

acetate,  133 

bichloride,  HgCl,,,  41 

blowpipe  test,  190 


254 


INDEX. 


Mercury,  chloride,  HgCI2,  41 

common  compounds  of,  27, 
40 

confirmed,  40 

cyanide,  41 

detected,  25,  32 

fulminate,  101 

iodide,  41 

nitric  oxide,  41 

oxide,  41 

perchloride,  HgCl2,  41 

protochloride,  27 

protonitrate,  27 

red  oxide,  41 

subchloride,  27 

sulphide,  41 

test  for,  240 

Metals  detected  by  blowpipe,  190 
by  borax  beads,  208 
by  colored  flames,  212 
Metaphosphoric  acid,  107 
Methylated  finish,  228 

spirit,  162 

Methylic  alcohol  identified,  62 
Microcosmic  salt,  108 
bead,  218 
for  testing,  236 

Milkiness  with  water,  29,  38,  49 
Milk-sugar  identified,  153 
Millon's  test,  160 
Mine  tin  ore,  125 
Minium,  29 

Molybdate  of  ammonia  for  test- 
ing, 236 

Molybdate  of  ammonia  test,  107 
Morphine,  acetate,  146 

detected,  144 

hydrochlorate,  146 

identified,  145 

meconate,  145 

muriate,  146 
Mortar,  118 
Mosaic  gold,  47 
Murexide  test  for  uric  acid,  131 

VTAPHTHALINE  identified,  158 
li      Narcotine  detected,  144 

identified,  147 
Needle-like  crystals,  28 
Nickel,  57 

blowpipe  test,  208 

confirmed,  57 

by  blowpipe,  211 


Nickel  detected,  51 

ores,  212 

oxide,  58 

speiss,  212 

sulphate,  58 

test  for,  229,  239 
Nicotine,  identified,  163 
Nitrate,  mercurous,  27 
Nitrate  of  baryta,  BaCNOg).,,  236 

of  bismuth,  39 

of  cobalt,  Co(N03)2,  236 

of  lead,  30 

of  potash  for  testing,  KN03, 
236 

of  silver,  AgN03,  26 
for  testing,  236 
Nitrates,  action  of  heat  on,  222 

blowpipe  test,  217 

on  charcoal,  223 
Nitre,  KN03,  81 

blowpipe  test,  219 

cubic,  88 
Nitric  acid,  HN03,  105 

confirmed,  105 

detected,  92 

for  testing,  237 

identified,  105 
Nitrites  detected,  105 
Nitrobenzole,  166 
Nitroprusside  of  sodium,  237 

for  testing,  237 
Nitrous  acid,  commercial,  106 

detected,  105 
Non-metals  detected,  91 

OCCLUSION  of  oxygen  by  silver, 
206 

Octahedra  of  arsenious  acid,  42 
Odors  of  organic  acids,  132 
Oil  of  bitter  almonds,  166 
vitriol,  102 

identified,  102 
Oleic  acid,  174 
Oleine,  174 
Orange  chrome,  29 
Organic  acid  detected  in  alkaline 

solution,  131 
detected     in      aqueous 

solution,  130 
detected     in     insoluble 

substance,  131 
acids  detected,  130 

by  odor,  132 


INDEX. 


255 


Organic  acids,  salts  of,  analyzed, 

132 

bases  identified,  144 
liquids  miscible  with  potash, 

164 

with  water,  162 
not  miscible  with  hydro- 
chloric acid,    potash, 
or  water,  165 
matter  detected,  96 
solids  tested,  149 
substances  denned,  96 
substances,  acid,  179 
bitter,  179 
dissolved     by     alcohol, 

156 
dissolved      by     boiling 

water,  154 
dissolved  by  cold  water, 

152 

dissolved  by  ether,  158 
evolving  ammonia,  177 
for  M.B.  examination, 

183 

fusible,  177 
identified,  149 
insoluble,  159 

in     boiling    water, 

179 

in  cold  water,  178 
liquid,  161 
nitrogenized,  177 
soluble  in  potash,  185 
sweet,  186 
unknown  examination, 

176 

volatile,  177 
Original  solution,  17 
Orpiment,  46 

Orthophosphoric  acid,  107 
Oxalate  of  ammonia  (NH4).2C204, 

237 

of  lime,  65,  74 
Oxalic  acid  confirmed,  111 
detected,  92 
identified,  111 
Oxidizing  flame,  191 
Oxygen  evolved,  82 

PALMITIC  acid  identified,  157 
Palmitine  identified,  158 
Paraffine  identified,  159 
Peacock  ore,  203 


Pearlash,  82 

Pearl  white,  39 

Perchloride  of  iron,  Fe2Cl6,  237 

mercury,  HgCl2,  238 
Perforated  corks,  171 
Permanganate  of  potash,  KMn04, 

63 

Peruvian  saltpetre,  88 
Pestle  arid  mortar.  118 
Pewter,  205 

Phenic  acid  identified,  150 
Phenole  identified,  150 
Phosphate  of  lime  detected,  64 
of  magnesia,  65 
of  magnesia  and  ammonia, 

65,  109 

of  soda,  Na2HP04,  89 
and  ammonia,  108 
for  testing,  238 
Phosphates,  10  3 

blowpipe  test,  226 
Phosphorescence,  65 
Phosphoric  acid,  blowpipe  test, 

226 

confirmed,  106 
detected,  92 
identified,  107 
test  for,  107 
tribasic,  107 

Phosphorus,  amorphous,  identi- 
fied, 108 
salt,  108 

vitreous,  identified,  107 
Picric  acid  identified,  149 
Pig-iron  identified,  53 
Pineapple  odor,  164 
Pink  salt,  48 
solution,  57 

sulphate  of  manganese,  63 
Pipe-clay,  127 
Plaster  of  Paris,  73 
Platina,  muriate,  229 
Platinic  chloride,  PtCl4,  229 
Platinum,  bichloride,  PtCl4,  229 
capsule,  121 
chloride,  PtCl4,  229 
corroded,  125 
foil,  120 

for  fusing,  120 
test  for,  231,  240 
wire  cleaned,  195 

for  borax  beads,  194 
colored  flames,  78 


Plumbago,  123 
Plumbic  acetate,  228 
Porcelain,  127 
Potash,  KHO,  83 

acetate,  134 

alum,  59 

antinioniate,  KSb03,  50 

bicarbonate,  83 

bichromate,  K20,2Cr03,  67 

binoxalate,  85 

bisulphate,  KHS04,  83 
blowpipe  test,  217 

bitartrate,  83,  138 

blowpipe  test,  222 

carbonate,  82 

caustic,  83 

chlorate,  82 

chromate,  67 

common  compounds  of,  81 

for  testing,  KHO,  238 

hydrate,  83 

hydriodate,  85 

rnaiiganate,  64 

nitrate,  KN03,  81 

oleate,  85 

oxalate,  85 

permanganate,  KMn04,  63 

prussiate,  84 

red  prussiate,  84 

silicate,  85 

solution  of,  KHO,  83 

sulphate,  83 
Potashes,  American,  82 
Potassafusa,  83 
Potassic  cyanide,  KCN,  84,  232     j 

dichromate,  67,  229 

ferridcyanide,  84,  232 

ferrocyanide,  84,  232 

hydrate,  KHO,  83,  238 

iodide,  KI,  85,  235 

nitrate,  KN03,  81,  236 
Potassium,  81 

blowpipe  test,  212 

carbonate,  82 

chloride,  83 

common  compounds  of,  81 

cyanide,  KCN,  84,  232 

detected,  77 

ferridcyanide,    K3FeCy6,  84, 
232 

ferrocyanide,    K4FeCy6,    84, 

232 
blowpipe  test,  214 


Potassium,  iodide,  KI,  85 

nitrate,  KN03,  81 

sulphate,  83 

sulphide,  99 

sulphocyanide,  101 
Powdering  substances,  118 
Precipitate  defined,  17 

washed,  33 

white,  41 

Precipitation  promoted  by   stir- 
ring, 22,  78 
Prepared  chalk,  73 
Preston  salts,  80 
Protochloride  of  tin  for  testing, 

SnCl2,  239 

Protosulphate  of  iron,  FeS04,  240 
Prussian  blue,  52,  56,  111 

test,  100 

Prussiate  of  potash,  84 
Prussic  acid,  101 

detected,  93 

identified,  101 
Pulverization,  118 
Pumice-stone,  128 
Purple  crystals,  67 

solution,  63 

vapors,  27,  94 
Putty  powders,  12f> 
Pyrites,  55 

copper,  203 

iron,  55 

Pyrogallic  acid  identified,  153 
Pyrogalline,  153 
Pyroligneous  acid,  133 

ether,  162 
Pyrolusite,  63 
Pyroxylic  spirit,  162 

QUARTZ,  126 
Quicklime,  72 
Quicksilver,  27 
Quinine  and  iron  citrate,  140 
detected,  144 
identified,  147 
sulphate,  147 

RAIN-WATER,  242 
Rat's-tail  file,  171 
Reagents,  228 
Realgar,  46 

Red  chlorosulphide  of  lead,  32 
chromate  of  lead,  29 
chromate  of  potash,  67 


INDEX. 


257 


Red  color  with  sulphuric  acid, 
154 

drops,  221 

flame,  71,  212 

haematite,  54 

iodide  of  arsenic,  46 

iodide  of  mercury,  41 

lead,  29 

litmus  paper,  235 

mordant,  60 

nitroprusside  of  sodium,  237 

orpiment,  46 

oxide  of  copper,  38 
iron,  54 
lead,  29 
mercury,  41 

phosphorus,  108 

precipitate,  41 

prussiate  of  potash,  84 

solution,  63,  67,  134 

sulphide  of  antimony,  49 
mercury,  41 

vapors,  91,  103 
Reducing  flame.  191 
Reduction  of  metals  on  charcoal, 

191 

Reinsch's  test  for  arsenic,  42 
Retort,  168 
Retort  stand,  94 
Ring  gas-burner,  169 
Roasting  before  blowpipe,  203 
Rochelle  salt,  139 
Rod,  breaking  and  rounding,  22 
Roll  brimstone,  122 
Rose  gas-burner,  169 
Rosin  identified,  157 
Rouge,  jeweller's,  55 
Rust,  55 

SAL-AMMONIAC,  79 
Salicine  detected  in  quinine, 
147 

identified,  154 
Saliretine,  154 
Sal  prunella,  82 
Salt,  88 

cake,  88 

common,  88 

of  lemon,  85 

of  sorrel,  85 

of  tartar,  82 
Saltpetre,  81 

flour,  82 


Saltpetre,  Peruvian,  88 

Sand,  126 

Scheele's  green,  37,  45 

Selenite,  73 

Shrapnel  bullets,  205 

Sifting,  119 

Silica,  126 

amorphous,  126 

detected,  113 

by  blowpipe,  224 

soluble,  126 
Silicic  acid,  126 

detected,  113 

by  blowpipe,  224 

separation    from    solutions, 

113 
Silicates,  common  simple,  127 

detected,  113 

on  charcoal,  223 

soluble,  114 
|  Silicium,  126 
i  Silicofluoric  acid,  233 
Silicon,  126 

fluoride,  97 

oxide,  126 
Silver  acetate,  133 

blowpipe  test,  201,  206 

chloride,  26,  103,  124 

in    blowpipe    analysis, 
206 

common  compounds  of,  26 

cyanide,  103 

detected,  25 

extracted  from  lead,  205 
Silver  ferridcyanide,  110 

ferrocyanide,  110 

identified,  26 

nitrate,  AgN03,  26 

oxalate,  112 

precipitates     distinguished, 
103 

test  for,  235 

tested  for  copper,  206 
Singed  hair,  odor  of,  132 
Slag,  iron,  56 
Slaked  lime,  72 
Slate,  127 
Smalt,  57 
Smelling  salts,  80 
Smell  of  almonds,  132,  166 

burnt  sugar,  137 

chlorine,  74 

gas,  158,  166 


09* 


258 


INDEX. 


Smell  of  incense,  136 
singed  hair,  132 
tar,  164 
Soap,  90 

soda,  90 
soft,  85 

Soap-stone,  128 
Soda,  acetate,  134 
aluminate,  60 
arseniate,  46 
ash,  88 
bibprate,  Na20.2B203,  89 

blowpipe  test,  226 
bicarbonate,  NaHCO3,  87 
carbonate,  Na.2C03,  87 
dried,  230 
for    blowpipe   analysis, 

193 

caustic,  88 
chloride,  89 
crystals,  87 
hydrate,  88 
hyposulphite,  89 

blowpipe  test,  215 
nitrate,  88 

blowpipe  test,  215 
orthophosphate,  89 
phosphate,  Na2HP04,  89 
silicate,  90 
stannate,  47 
sulphate,  88 
sulphite,  89 
tungstate,  90 
urate,  142 
waste,  100 

Sodic  carbonate,  87,  230 
Sodium,  blowpipe  test,  212 
carbonate,  87 
chloride,  88 

common  compounds  of,  87 
detected,  77 
flame  deceptive,  214 
hyposulphite,  89 
jmpurity,  214 
'nitrate,  88 
phosphate,  89 
sulphate,  88 
sulphite,  89 
Soft  soap,  85 
Solder,  205 

Solid   unknown    substances   ex- 
amined, 181 
Soluble  glass,  90 


Solution,  19 
Soot  identified,  124 
Spathic  iron  ore,  56 
Spatula,  118 
Specular  iron  pre,  54 
Speiss,  212 
Spelter  (zinc),  60 
Spermaceti  identified,  159 
Spirit-black,  123 
Spirit-blowpipe,  173 
Spirit-lamp,  19 
Spirit  of  wine,  162 
Spirting,  prevention  of,  94 
Spongy  flakes  of  sulphur,  41 
Stannate  of  soda,  47 
Stannic  acid,  47,  125 

chloride,  48 

compounds,  47 

Stannous    chloride,    SnCL,    36, 
234 

compounds,  36 
Starch  for  testing,  240 

identified,  154 

sugar,  152 

test  for,  235 

Steam-bath  for  evaporation,  174 
Stearic  acid  identified,  157 
Stearine  identified,  156 
Steatite,  128 
Steel  identified,  53 
Stirring,  22 

rod,  22 

to  promote  precipitation,  22, 

78 

Stoppers,  India-rubber,  172 
Stourbridge  clay,  127 
Stream  tin  ore,  125 
Strong  sulphuric  acid,  H2S04,  241 
Strontia,  carbonate,  71 

detected,  68 

nitrate,  71 

sulphate,  125 
Strontianite,  71 
Strontium,  70 

blowpipe  test,  212 

confirmed,  70 

detected,  68 
Strychnine  detected,  144 

identified,  146 
Sublimate  corrosive,  41 
Sublimation,  J36 
Succinic  acid  detected,  130 

identified,  13C 


INDEX. 


259 


Sugar,  152 

copper  test  for,  152 

identified,  152 

of  lead,  29 

Sulphate  of  copper,  CuS04,  37 
for  testing,  240 

of  iron  for  testing,  FeS04,  240 

lead,  30 

of  lime  for  testing,   CaS04, 
240 

of  niagnesia,  MgS04,  24 
for  testing,  240 

of  manganese  for  testing, 
MnSO4,  240 

of  zinc,  61 
Sulphates,  action  of  heat  on,  221 

blowpipe  test,  224 

detected,  92 

impurities,  102 

insoluble,  125 
Sulphide  of  ammonium,  (NH4)2S, 

80 
for  testing,,  233 

of  ammonium  precipitate,  51 

of  antimony,  49 

of  arsenic,  46 

of  copper,  38 

of  iron,  55 

of  lead,  30 

of  tin,  36 

of  zinc,  61 
Sulphides,  action  of  heat  on,  222 

common,  99 

detected,  91 

by  blowpipe,  225 

on  charcoal,  223 
Sulphites  detected,  91 
Sulphocyanides  detected,  92 

test  for.  241 
Sulphur,  122 

blowpipe  test,  222 

crude,  122 

detected,  91 

by  blowpipe,  222 

distilled,  122 

evolved,  222 

expelled  by  roasting,  203 

flowers  of.  122 

identified,  122 

insoluble,  122 

milk  of,  122 

precipitated,  122 

precipitation  of,  23 


Sulphur  roll,  122 
Sicilian,  122 
soluble,  122 
sublimed,  122 
viscous,  122 

Sulphurets,  common,  99 
Sulphuretted  hydrogen  appara- 
tus, 234 

identified,  98 

precipitate,  32 

prepared,  233 

test  for,  228 
Sulphuric  acid,  H2S04,  102 

blowpipe  test,  224 

detected,  92 

for  testing,  241 

identified,  102 

Nordhausen,  102 

test  for,  236 
Sulphurous  acid  confirmed,  101 

detected,  91 

evolved,  223 

Sulphydrate  of  ammonium,  233 
Superphosphate  of  Hme,  t>4 
Sweet  substances,  1*86 
Sweet  taste,  29 
Sylvic  acid,  158 

'TABLE  A,  page    17 


1 


B, 
C, 


F, 

G, 


L, 

M, 
N, 

0, 
P, 

Q, 
R, 

B, 
T, 
U, 
V, 

w, 

x, 
Y, 


25 

32 

51 

68 

77 

91 

92,  93 
116 
129 
130 
131 
131 
144 
151 
161 
190 
201 
208 
212 
216 
217 
221 
223 
224 


INDEX. 


Taiinic  acid  detected,  130 
identified,  135 
test  for,  238 
Tannin,  135 
Tartar,  cream  of,  83 
emetic,  49 

blowpipe  test,  202 
salt  of,  82 

Tartaric  acid,  H2C4H406,  137 
detected,  130 
for  testing,  241 
identified,  137 
Tartrates,  action  of  heat  on,  222 

common,  138 
Test  papers,  235,  241 

use  of,  34 
tube,  19 

rack,  19 
Tests,  228 

addition  of,  21 
Theine  detected,  145 

identified,  145 
Thermometer,  168 
Tin,  35 

alloys  of,  205 
before  blowpipe,  207 
bichloride,  48 
bichloride  with  hydrochlo- 

rate  of  ammonia,  48 
binoxide,  47,  125 
bisulphide,  47 
blowpipe  test,  201 
common   compounds  of,  36, 

47 

confirmed,  35,  46 
crystals,  36 
detected,  32 

by  blowpipe,  201 
foil,  239 
granulated,  239 
identified,  35 

in  insoluble  substances,  125 
nitromuriate,  48 
ore,  125 
persalts  of,  47 
plate,  207 

protochloride,  SnCl2,  36 
protosalts  of,  36 
protosulphide,  36 
pyrites,  36 

reduction  on  charcoal,  190 
salts  of,  36,  47 
stone,  125 


Tin  test  for,  238 

Tincture  of  iron,  56 

Toluidine,  164 

Tongs,  117 

Triangle,  117 

Triple  phosphate,  65,  109 

Tube,  blowpipe  test  in,  221 

funnel,  170 

German,  33 
Tubes,  bent,  172 

sealed,  33 

Tubulated  retort,  168 
Tubulus,  168 
Tungstate  of  soda,  blowpipe  test, 

215 

Tungstic  acid  detected,  90 
Turmeric,  241 

paper,  241 
Type-metal,  205 

TTLTRAMARINE,  100 
U      University  of    London    ex- 
amination, 183 
Unknown  liquid  examined,  181 

solid  examined,  181 
Urates,  common,  142 
Urea  identified,  153 
nitrate,  155 
oxalate,  155 
Uric  acid  confirmed,  141 
detected,  131 
identified,  141 

VALERIANIC  acid,  164 
Verdigris,  37 
Vermilion,  41 

antimony,  49 
Vinegar,  133 
Violet  flame,  81 
Vitriol,  blue,  37 

green,  55 

identified,  102 

white,  61 


w 


CASHING  bottle,  33 
precipitates,  33 


Washing-soda,  87 
Water,  H20,  181 
Water-bath,  174 
Water  for  testing,  241 

glass,  90 

purification,  242 

tested  for  impurities,  242 


INDEX. 


201 


Wax,  identified,  159 
White  lead,  29 

precipitate,  41 

vitriol,  61 
Wire  triangle,  117 
Witherite,  69 
Wood-charcoal,  123 
Wood-naphtha,  162 
Wood-spirit,  163 

YELLOW  chromate  of  baryta, 
70 

of  potash,  67 
chrome,  29 
'  flame,  212 
fused  mass,  124 
iodide  of  lead,  30 

of  mercury,  41 
orpiment,  46 
oxide  of  lead,  28 
oxychloride  of  lead,  30 
picric  acid,  149 


Yellow  prussiate  of  potash,  84 
sulphide  of  tin,  47 

ZEOLITES,  114 
Zeolitic  minerals,  114 
Zinc  before  blowpipe,  208 
blowpipe  test,  190 
carbonate,  61 
chloride,  62 

common  compounds  of,  61 
confirmed,  60 
detected,  51 
glance,  128 
granulated,  43 
identified,  60 
lactate,  174 
oxide,  61 
silicate,  128 
sulphate,  61 
sulphide,  61 
test  for,  235 
white,  61 


CATALOGUE  No.  7, 


MAY,   1889. 


A  CATALOGUE 

OF 

BOOKS  FOR  STUDENTS. 

INCLUDING   THE 

?  QUIZ-COMPENDS  ? 


c< 

PJ 
New  Series  of  Manuals,  2,3 
Anatomy, 
Biology, 

3NTENTS. 

VGE                                                                                PAGE 

4,5    '    Obstetrics.     .         .         .         .10 
6    j    Pathology,  Histology,  .         .  n 
ii     j    Pharmacy,     .         .         .         •  *3 
6        Physical  Diagnosis,      .         .11 
7        Physiology,  .         .         .         .12 
8        Practice  of  Medicine,    .         .  12 
8        Prescription  Books,       .         .  12 
8       PQuiz-Compends  ?     .     15,16 
9        Skin  Diseases,       .         .         .13 

Chemistry, 
Children's  Diseases,     . 
Dentistry, 
Dictionaries, 
Eye  Diseases, 
Electricity,    . 
Gynaecology, 
Hygiene, 
Materia  Medica,  . 
Medical  Jurisprudence, 
Miscellaneous, 

9        Therapeutics,         .         .         .9 
9       Throat,          .        .        .         .14 
9        Urjne  and  Urinary  Organs,     14 
10       Venereal  Diseases,        .        .  14 

PUBLISHED   BY 


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No.  1.     SURGERY.     236  Illustrations. 
A    Manual   of    the   Practice  of    Surgery.     By  WM.  J. 

WALSHAM,  M.D.,  Asst.  Surg.  to,  and  Demonstrator  of 

Surg.   in,  St.   Bartholomew's   Hospital,   London,  etc. 

228  Illustrations. 

Presents  the  introductory  facts  in  Surgery  in  clear,  precise 
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The  Diseases  of  Women.  By  DR.  F.  WINCKEL, 
Professor  of  Gynaecology  and  Director  of  the  Royal 
University  Clinic  for  Women,  in  Munich.  Translated 
from  the  German  by  DR.  J.  H.  WILLIAMSON,  Resident 
Physician  Allegheny  General  Hospital,  Allegheny, 
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No.  3.    OBSTETRICS.    227  Illustrations. 
A  Manual  of  Midwifery.     By  ALFRED  LEWIS  GALABIN, 
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wifery and  the  Diseases  of  Women  at  Guy's  Hospital, 
London;     Examiner   in    Midwifery   to   the    Conjoint 
Examining  Board  of  England,  etc.     With  227  Illus. 
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Students   at  the  present  time  not  only  are  expected  to  know  the 
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No.  4.    PHYSIOLOGY.    Third  Edition. 

321  ILLUSTRATIONS  AND  A  GLOSSARY. 
A  Manual  of    Physiology.     By  GERALD  F.  YEO,  M.D., 

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and  improved.     758  pages. 

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No.  5.  POTTER'S  MATERIA  MEDICA, 
PHARMACY  AND  THERAPEUTICS. 

OVER  600  PRESCRIPTIONS,  FORMULAE,  ETC. 
A  Handbook  of  Materia  Medica,  Pharmacy  and 
Therapeutics — including  the  Physiological  Action  of 
Drugs,  Special  Therapeutics  of  Diseases,  Official  and 
Extemporaneous  Pharmacy,  etc.,  etc.  By  SAM'L 
O.  L.  POTTER,  M.A.,  M.D.,  Professor  of  the  Practice  of 
Medicine  in  Cooper  Medical  College,  San  Francisco, 
Late  A.  A.  Surg.,  U.  S.  A.,  Author  of  the  "  Quiz- 
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This  book  contains  many  unique  features  of  style  and  arrange- 
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put  together,  also  many  tables,  dose  lists,  diagnostic  hints,  etc., 
all  rendering  it  the  most  complete  manual  ever  published. 

4SF"  Part  III,  Special  Therapeutics,  consists  of  an  Alpha- 
betical List  of  Diseases,  in  which  is  given  the  proper  drugs 
to  be  used  in  the  treatment  of  each,  with  the  authority 
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tions. This  will  be  found  of  great  value  to  the  young  practi- 
tioner, and  to  the  physician  of  experience  it  will  suggest 
new  methods  of  treatment  in  obstinate  and  chronic  cases. 

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Medical  Journal. 

No.  6.    DISEASES  OF  CHILDREN. 

A  Manual.  By  J.  F.  GOODHART,  M.D.,  Phys.  to  the 
Evelina  .Hospital  for  Children ;  Asst.  Phys.  to 
Guy's  Hospital,  London.  American  Edition.  Edited 
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Directions  for  making  Artificial  Human  Milk,  for  the 
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members  of  the  profession.  In  these  days  of  prolixity  in  medical 
literature,  it  is  refreshing  to  meet  with  an  author  who  knows  both 
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THE   NEW  SERIES  OF  MANUALS. 


(admirably  conformed,  by  Dr.  Starr,  to  meet  American  require- 
ments) is  the  nearest  approach  to  clinical  teaching  without  the 
actual  presence  of  clinical  material  that  we  have  yet  seen." — New 
York  Medical  Record. 

No.  7-    PRACTICAL,  THERAPEUTICS. 

FOURTH  EDITION,  WITH  AN  INDEX  OF  DISEASES. 

Practical  Therapeutics,  considered  with  reference  to 
Articles  of  the  Materia  Medica.  Containing,  also,  an 
Index  of  Diseases,  with  a  list  of  the  Medicines 
applicable  as  Remedies.  By  EDWARD  JOHN  WARING, 
M.D.,  F.R.C.P.  Fourth  Edition.  Rewritten  and  Re- 
vised. By  DUDLEY  W.  BUXTON,  M.D.,  Asst.  to  the 
Prof,  of  Medicine  at  University  College  Hospital. 

"  We  wish  a  copy  could  be  put  in  the  hands  of  every  Student  or 
Practitioner  in  the  country.  In  our  estimation,  it  is  the  best  book 
of  the  kind  ever  written." — N.  Y.  Medical  Journal. 

No.  8.    MEDICAL,  JURISPRUDENCE  AND 
TOXICOLOG-Y.    New  Ed. 

By  John  J.  Reese,  M.D.,  Professor  of  Medical  Jurispru- 
dence and  Toxicology  in  the  University  of  Pennsyl- 
vania ;  President  of  the  Medical  Jurisprudence  Society 
of  Phila. ;  2d  Edition,  Revised  and  Enlarged. 

"This  admirable  text-book." — Amer.Jour.  of  Med.  Sciences. 

"  We  lay  this  volume  aside,  after  a  careful  perusal  of  its  pages, 
with  the  profound  impression  that  it  should  be  in  the  hands  of  every 

doctor  and  lawyer.  It  fully  meets  the  wants  of  all  students 

He  has  succeeded  in  admirably  condensing  into  a  handy  volume  all 
the  essential  points." — Cincinnati  Lancet  and  Clinic. 

No.  9.    ORGANIC  CHEMISTRY. 

Or  the  Chemistry  of  the  Carbon  Compounds.  By  Prof. 
VICTOR  VON  RICHTER,  University  of  Breslau.  Au- 
thorized translation,  from  the  Fourth  German  Edition. 
By  EDGAR  F.  SMITH,  M.A.,  PH.D.  ;  Prof,  of  Chemistry 
in  University  of  Pennsylvania;  Member  of  the  Chem. 
Socs.  of  Berlin  and  Paris. 

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of  Chemistry,  Jefferson  Medical  College,  Philadelphia. 

"  This  work  brings  the  whole  matter,  in  simple,  plain  language, 
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method  of  the  work  is  one  that  is-  more  readily  grasped  than  that  of 
older  and  more  famed  text-books,  and  we  look  forward  to  the  time 
when,  to  a  great  extent,  this  work  will  supersede  others,  on  the 
score  of  its  better  adaptation  to  the  wants  of  both  teacher  and 
student." — Pharmaceutical  Record. 

Price  of  each  Book,  Cloth,  $3.00 ;  Leather,  $3.50. 


6          STUDENTS'  TEXT-BOOKS  AND  MANUALS. 

ANATOMY. 

Holden's  Anatomy.  A  manual  of  Dissection  of  the  Human 
Body.  Fifth  Edition.  Enlarged,  with  Marginal  References  and 
over  200  Illustrations.  Octavo;  Cloth,  5.00;  Leather,  6.00 

Bound  in  Oilcloth,  for  the  Dissecting  Room,  $4.50. 

"  No  student  of  Anatomy  can  take  up  this  book  without  being 
pleased  and  instructed.  Its  Diagrams  are  original,  striking  and 
suggestive,  giving  more  at  a  glance  than  pages  of  text  description. 
*  *  *  The  text  matches  the  illustrations  in  directness  of  prac- 
tical application  and  clearness  of  detail." — New  York  Medical 
Record. 

Holden's  Human  Osteology.  Comprising  a  Description  of  the 
Bones,  with  Colored  Delineations  of  the  Attachments  of  the 
Muscles.  The  General  and  Microscopical  Structure  of  Bone  and 
its  Development.  With  Lithographic  Plates  and  Numerous  Illus- 
trations. Seventh  Edition.  8vo.  Cloth,  6.00 

Holden's  Landmarks,  Medical  and  Surgical.     4th  ed. 

Cloth,  1.25 

Heath's  Practical  Anatomy.  Sixth  London  Edition.  24  Col- 
ored Plates,  and  nearly  300  other  Illustrations.  Cloth,  5.00 

Potter's  Compend  of  Anatomy.  Fourth  Edition.  117  Illus- 
trations. Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

CHEMISTRY. 

Hartley's  Medical  Chemistry.    A  text-book  prepared  specially 
for  Medical,   Pharmaceutical  and    Dental    Students.     With  40 
Illustrations,  Plate  of  Absorption  Spectra  and  Glossary  of  Chemi- 
cal Terms.  Cloth,  2.50 
***  This  book  has  been  written  especially  for  students  and  phy- 
sicians.    It  is  practical  and  concise,  dealing  only  with  those  parts 
of  chemistry  pertaining  to  medicine ;  no  time  being  wasted  in  long 
descriptions   of  substances  and  theories   of    interest  only  to   the 
advanced  chemical  student. 

Bloxam's  Chemistry,  Inorganic  and  Organic,  with  Experiments. 
Sixth  Edition.  Enlarged  and  Rewritten.  Nearly  300  Illus- 
trations. Cloth,  4.50 ;  Leather,  5.50 

Richter's  Inorganic  Chemistry.  A  text-book  for  Students. 
Third  American,  from  Fifth  German  Edition.  Translated  by 
Prof.  Edgar  F.  Smith,  PH.D.  89  Wood  Engravings  and  Colored 
Plate  of  Spectra.  Cloth,  2.00 

Richter's  Organic  Chemistry,  or  Chemistry  of  the  Carbon 
Compounds.  Translated  by  Prof.  Edgar  F.  Smith,  PH.D. 
Illustrated.  Cloth,  3.00;  Leather,  3.50 

ee  pages  2  to  j  for  list  of  Students'  Manuals. 


STUDENTS'  TEXT-BOOKS  AND  MANUALS.         7 

Chemistry  : — Continued. 

Trimble.  Practical  and  Analytical  Chemistry.  A  Course  in 
Chemical  Analysis,  by  Henry  Trimble,  Prof,  of  Analytical  Chem- 
istry in  the  Phila.  College  of  Pharmacy.  Illustrated.  Second 
Edition.  8vo.  Cloth,  1.50 

Tidy.     Modern  Chemistry.    2d  Ed.  Cloth,  5.50 

Leffmann's  Compend  of  Chemistry.  Inorganic  and  Organic. 
Including  Urinary  Analysis  and  the  Sanitary  Examination  of 
Water.  New  Edition.  Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

Muter.  Practical  and  Analytical  Chemistry.  Second  Edi- 
tion. Revised  and  Illustrated.  Cloth,  2.00 

Holland.  The  Urine,  Common  Poisons,  and  Milk  Analysis, 
Chemical  and  Microscopical.  For  Laboratory  Use.  sd 
Edition,  Enlarged.  Illustrated.  In  Press. 

Van  Niiys.     Urine  Analysis.     Illus.  Cloth,  2.00 

Wolff's  Applied  Medical  Chemistry.  By  Lawrence  Wolff, 
M.D.,  Demonstrator  of  Chemistry  in  Jefferson  Medical  College, 
Philadelphia.  Cloth,  i.oo 

CHILDREN. 

Goodhart  and  Starr.  The  Diseases  of  Children.  A  Manual 
for  Students  and  Physicians.  By  J.  F.  Goodhart,  M.D.,  Physi- 
cian to  the  Evelina  Hospital  for  Children ;  Assistant  Physician 
to  Guy's  Hospital,  London.  American  Edition,  Revised  and 
Edited  by  Louis  Starr,  M.D.,  Clinical  Professor  of  Diseases  of 
Children  in  the  Hospital  of  the  University  of  Pennsylvania; 
Physician  to  the  Children's  Hospital,  Philadelphia.  Containing 
many  new  Prescriptions,  a  List  of  over  50  Formulae,  conforming 
to  the  U.  S.  Pharmacopoeia,  and  Directions  for  making  Arti- 
ficial Human  Milk,  for  the  Artificial  Digestion  of  Milk,  etc. 

Cloth,  3.00;  Leather,  3.50 

Day.  On  Children.  A  Practical  and  Systematic  Treatise. 
Second  Edition.  8vo.  752  pages.  Cloth,  3.00;  Leather,  4.00 

Meigs  and  Pepper.  The  Diseases  of  Children.  Seventh 
Edition.  8vo.  Cloth,  5.00;  Leather,  6.00 

Starr.  Diseases  of  the  Digestive  Organs  in  Infancy  and 
Childhood.  With  chapters  on  the  Investigation  of  Disease, 
and  on  the  General  Management  of  Children.  By  Louis  Starr, 
M.D.,  Clinical  Professor  of  Diseases  of  Children  in  the  Univer- 
sity of  Pennsylvania;  with  a  section  on  Feeding,  including  special 
Diet  Lists,  etc.  Illus.  Cloth,  2.50 

49-  See  pages  13  and  ib  for  list  of  f  Quiz-  Compends  f 


8          STUDENTS'  TEXT-BOOKS  AND  MANUALS. 

DENTISTRY. 

Fillebrown.  Operative  Dentistry.  330  Illustrations.  Just 
Ready.  Cloth,  2.50 

Flagg's  Plastics  and  Plastic  Filling.     3d  Ed.         Preparing. 

Gorgas.  Dental  Medicine.  A  Manual  of  Materia  Medica  and 
Therapeutics.  Third  Edition.  Cloth,  3.25 

Harris.  Principles  and  Practice  of  Dentistry.  Including 
Anatomy,  Physiology,  Pathology,  Therapeutics,  Dental  Surgery 
and  Mechanism.  Twelfth  Edition.  Revised  and  enlarged  by 
Professor  Gorgas.  1028  Illustrations.  Cloth,  7.00  ;  Leather,  8.00 

Richardson's  Mechanical  Dentistry.  Fifth  Edition.  569 
Illustrations.  8vo.  Cloth,  4.50;  Leather,  5.50 

Stocken's  Dental  Materia  Medica.  Third  Edition.  Cloth,  2.50 

Taft's  Operative  Dentistry.  Dental  Students  and  Practitioners. 
Fourth  Edition.  100  Illustrations.  Cloth,  4.25  ;  Leather,  5.00 

Talbot.  Irregularities  of  the  Teeth,  and  their  Treatment. 
Illustrated.  8vo.  Cloth,  2.00 

Tomes'  Dental  Anatomy.     Third  Ed.      191  Illus.     Preparing. 

Tomes'  Dental  Surgery.  3d  Edition.  Revised.  292  Illus. 
772  Pages.  Cloth,  5.00 

DICTIONARIES. 

Cleaveland's  Pocket  Medical  Lexicon.    Thirty-first  Edition. 

Giving  correct  Pronunciation  and  Definition  of  Terms  used  in 

Medicine  and  the  Collateral  Sciences.     Very  small  pocket  size. 

Cloth,  red  edges  .75  ;  pocket-book  style,  i.oo 

Longley's  Pocket  Dictionary.  The  Student's  Medical  Lexicon, 
giving  Definition  and  Pronunciation  of  all  Terms  used  in  Medi- 
cine, with  an  Appendix  giving  Poisons  and  Their  Antidotes, 
Abbreviations  used  in  Prescriptions,  Metric  Scale  of  Doses,  etc. 
24mo.  Cloth,  i.oo;  pocket-book  style,  1.25 

EYE. 

Arlt.  Diseases  of  the  Eye.  Including  those  of  the  Conjunc- 
tiva, Cornea,  Sclerotic,  Iris  and  Ciliary  Body.  By  Prof.  Von 
Arlt.  Translated  by  Dr.  Lyman  Ware.  Illus.  8vo.  Cloth,  2.50 

Hartridge  on  Refraction.    3d  Ed.  Cloth,  2.00 

Macnamara.  Diseases  of  the  Eye.  4th  Edition.  Revised. 
Colored  Plates  and  Wood  Cuts  and  Test  Types.  Cloth,  4.00 

Meyer.  Diseases  of  the  Eye.  A  complete  Manual  for  Stu- 
dents and  Physicians.  270  Illustrations  and  two  Colored  Plates. 
8vo.  Cloth,  4.50;  Leather,  5.50 

Fox  and  Gould.  Compend  of  Diseases  of  the  Eye  and 
Refraction.  2d  Ed.  Enlarged.  71  Illus.  39  Formulae. 

Cloth,  i.oo  ;  Interleaved  for  Notes,  1.25 

JiSr"  See  pages  2  to  5  for  list  of  Students'  Manuals. 


STUDENTS'  TEXT-BOOKS  AND  MANUALS.          9 

ELECTRICITY. 

Mason's  Compend  of  Medical  and  Surgical  Electricity. 
With  numerous  Illustrations.  i2mo.  Cloth,  i.oo 

HYGIENE. 

Parkes'  Practical  Hygiene.     Seventh  Edition,  enlarged.    Illus- 
trated.   8vo.  Cloth,  4.50 
Wilson's    Handbook  of  Hygiene  and   Sanitary   Science. 

Sixth  Edition.     Revised  and  Illustrated.  Cloth,  2.75 

MATERIA  MEDICA  AND  THERAPEUTICS. 

Potter's  Compend  of  Materia  Medica,  Therapeutics  and 

Prescription  Writing.     Fifth  Edition,  revised  and  improved. 

Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

Biddle's  Materia  Medica.  Eleventh  Edition.  By  the  late 
John  B.  Biddle,  M.D.,  Professor  of  Materia  Medica  in  Jefferson 
Medical  College,  Philadelphia.  Thoroughly  revised,  and  in  many 
parts  rewritten,  by  his  son,  Clement  Biddle,  M.D.,  Assistant 
Surgeon,  U.  S.  Navy,  assisted  by  Henry  Morris,  M.D.,  Demon- 
strator of  Obstetrics  in  Jefferson  Medical  College.  8vo.,  illus- 
trated. Cloth,  4.25;  Leather,  5.00 

Headland's  Action  of  Medicines,    gih  Ed.    8vo.      Cloth,  3.00 

Potter.  Materia  Medica,  Pharmacy  and  Therapeutics. 
Including  Action  of  Medicines,  Special  Therapeutics,  Pharma- 
cology, etc.  Page  4.  Cloth,  3.00;  Leather,  3.50 

Starr,  Walker  and  Powell.  Synopsis  of  Physiological 
Action  of  Medicines,  based  upon  Prof.  H.  C.  Wood's  "  Materia 
Medica  and  Therapeutics."  3d  Ed.  Enlarged.  Cloth,  .75 

Waring.  Therapeutics.  With  an  Index  of  Diseases  and  an 
Index  of  Remedies.  A  Practical  Manual.  Fourth  Edition. 
Revised  and  Enlarged.  Cloth,  3.00;  Leather,  3.50 

MEDICAL  JURISPRUDENCE. 

Reese.  A  Text-book  of  Medical  Jurisprudence  and  Toxi- 
cology. By  John  J.  Reese,  M.D.,  Professor  of  Medical  Juris- 
prudence and  Toxicology  in  the  Medical  Department  of  the 
University  of  Pennsylvania;  President  of  the  Medical  Juris- 
prudence Society  of  Philadelphia ;  Physician  to  St.  Joseph's 
Hospital ;  Corresponding  Member  of  The  New  York  Medico- 
legal  Society.  2d  Edition.  Cloth,  3.00 ;  Leather,  3.50 

Woodman  and  Tidy's  Medical  Jurisprudence  and  Toxi- 
cology. Chromo-Lithographic  Plates  and  116  Wood  engravings. 

Cloth,  7.50;  Leather,  8.50 

J86S°"  See  pages  15  and  ib  for  list  of  fQuiz-Compends  ? 


10        STUDENTS'   TEXT-BOOKS   AND   MANUALS. 

MISCELLANEOUS. 

Allingham.  Diseases  of  the  Rectum.  Fourth  Edition.  Illus- 
trated. 8vo.  Paper  covers,  .75;  Cloth,  1.25 

Beale.     Slight  Ailments.     Their  Nature  and  Treatment.     Illus- 
trated.    8vo.  Paper  cover,  .75  ;  Cloth,  1.25 
Domville  on  Nursing.    6th  Edition.  Cloth,  .75 

Fothergill.  Diseases  of  the  Heart,  and  Their  Treatment. 
Second  Edition.  8vo.  Cloth,  3.50 

Gowers.  Diseases  of  the  Nervous  System.  341  Illus- 
trations. Cloth,  6.50 ;  Leather,  7.50 

Mann's  Manual  of  Psychological  Medicine,  and  Allied  Ner- 
vous Diseases.  Their  Diagnosis,  Pathology  and  Treatment,  and 
their  Medico-Legal  Aspects.  Illus.  Cloth,  5.00 ;  Leather,  6.00 

Tanner.  Memoranda  of  Poisons.  Their  Antidotes  and  Tests. 
Sixth  Edition.  Revised  by  Henry  Leffmann,  M.D.  Cloth,  .75 

OBSTETRICS  AND  GYN^COLOGY. 

Byford.  Diseases  of  Women.  The  Practice  of  Medicine  and 
Surgery,  as  applied  to  the  Diseases  and  Accidents  Incident  to 
Women.  By  W.  H.  Byford,  A.M.,  M.D.,  Professor  of  Gynaecology 
in  Rush  Medical  College  and  of  Obstetrics  in  the  Woman's  Med- 
ical College,  etc.,  and  Henry  T.  Byford,  M.D.,  Surgeon  to  the 
Woman's  Hospital  of  Chicago ;  Gynaecologist  to  St.  Luke's 
Hospital,  etc.  Fourth  Edition.  Revised,  Rewritten  and  En- 
larged. With  306  Illustrations,  over  100  of  which  are  original. 
Octavo.  832  pages.  Cloth,  5.00  ;  Leather,  6.00 

Cazeaux  and  Tarnier's  Midwifery.  With  Appendix,  by 
Munde.  The  Theory  and  Practice  of  Obstetrics  ;  including  the 
Diseases  of  Pregnancy  and  Parturition,  Obstetrical  Operations, 
etc.  By  P.  Cazeaux.  Remodeled  and  rearranged,  with  revi- 
sions and  additions,  by  S.  Tarnier,  M.D.,  Professor  of  Obstetrics 
and  Diseases  of  Women  and  Children  in  the  Faculty  of  Medicine 
of  Paris.  Eighth  American,  from  the  Eighth  French  and  First 
Italian  Edition.  Edited  by  Robert  J.  Hess,  M.D.,  Physician  tp 
the  Northern  Dispensary,  Philadelphia,  with  an  appendix  by 
Paul  F.  Munde,  M.D.,  Professor  of  Gynaecology  at  the  N.  Y. 
Polyclinic.  Illustrated  by  Chromo- Lithographs,  Lithographs, 
and  other  Full-page  Plates,  seven  of  which  are  beautifully  colored, 
and  numerous  Wood  Engravings.  Students'  Edition.  One 
Vol.,  8vo.  Cloth,  5.00;  Leather,  6.00 

Lewers'  Diseases  of  Women.  A  Practical  Text-Book.  139 
Illustrations.  Cloth,  2.25 

Parvin's  Winckel's  Diseases  of  Women.  Edited  by  Prof. 
Theophilus  Parvin,  Jefferson  Medical  College,  Philadelphia. 
117  Illustrations.  See  page  3.  Cloth,  3.00;  Leather,  3.50 

Morris.    Compend  of  Gynaecology.    Illustrated.      In  Press. 
%S~  See  pages  2  to  5 for  list  of  New  Manuals. 


STUDENTS'  TEXT-BOOKS  AND  MANUALS.         11 

Obstetrics  and  Gyncec ology  :—  Continued. 

Winckel's  Obstetrics.  A  Text-book  on  Midwifery,  includ- 
ing the  Diseases  of  Childbed.  By  Dr.  F.  Winckel,  Professor 
of  Gynaecology,  and  Director  of  the  Royal  University  Clinic  for 
Women,  in  Munich.  Authorized  Translation,  by  J.  Clifton 
Edgar,  M.D.,  Lecturer  on  Obstetrics,  University  Medical  Col- 
lege, New  York,  with  nearly  200  handsome  illustrations,  the 
majority  of  which  are  original  with  this  work.  Octavo.  In  press. 

Landis'  Compend  of  Obstetrics.  Illustrated.  4th  edition, 
enlarged.  Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

Galabin's  Midwifery.  A  New  Manual  for  Students.  By  A. 
Lewis  Galabin,  M.D.,  F.R.C.P.,  Obstetric  Physician  to  Guy's 
Hospital,  London,  and  Professor  of  Obstetrics  in  the  same  Insti- 
tution. 227  Illustrations.  See  page  3.  Cloth,  3.00;  Leather,  3.50 

Glisan's  Modern  Midwifery.     2d  Edition.  Cloth,  3.00 

Rigby's  Obstetric  Memoranda.  By  Alfred  Meadows,  M.D. 
4th  Edition.  Cloth,  .50 

Meadows'  Manual  of  Midwifery.  Including  the  Signs  and 
Symptoms  of  Pregnancy,  Obstetric  Operations,  Diseases  of  the 
Puerperal  State,  etc.  145  Illustrations.  494  pages.  Cloth,  2.00 

Swayne's  Obstetric  Aphorisms.  For  the  use  of  Students 
commencing  Midwifery  Practice.  8th  Ed.  i2mo.  Cloth,  1.25 

PATHOLOGY.    HISTOLOGY.    BIOLOGY. 

Bowlby.  Surgical  Pathology  and  Morbid  Anatomy,  for 
Students.  135  Illustrations.  i2mo.  Cloth,  2.00 

Davis'  Elementary  Biology.     Illustrated.  Cloth,  4.00 

Rindfleisch's  General  Pathology.  By  Prot.  Edward  Rind- 
fleisch.  Translated  by  Wm.  H.  Mercur,  M.D.  Edited  by  James 
Tyson,  M.D.,  Professor  of  Clinical  Medicine  in  the  University 
of  Pennsylvania.  i2mo.  Cloth,  2.00 

Gilliam's  Essentials  of  Pathology.  A  Handbook  for  Students. 
47  Illustrations.  i2mo.  Cloth,  2.00 

*#*The  object  of  this  book  is  to  unfold  to  the  beginner  the  funda- 
mentals of  pathology  in  a  plain,  practical  way,  and  by  bringing 
them  within  easy  comprehension  to  increase  his  interest  in  the  study 
of  the  subject. 

Gibbes'  Practical  Histology  and  Pathology.     Third  Edition. 

Enlarged.     i2mo.  Cloth,  1.75 

Virchow's  Post-Mortem  Examinations.     2d  Ed.    Cloth,  i.oo 

PHYSICAL  DIAGNOSIS. 

Bruen's  Physical  Diagnosis  of  the  Heart  and  Lungs.  By 
Dr.  Edward  T.  Bruen,  Assistant  Professor  of  Clinical  Medicine 
in  the  University  of  Pennsylvania.  Second  Edition,  revised. 
With  new  Illustrations.  a2mo.  Cloth,  1.50 

e  pages  75  and  ib  for  list  of  ?  Quiz-Compends  t 


12        STUDENTS'   TEXT-BOOKS   AND   MANUALS. 


PHYSIOLOGY. 

Yeo's  Physiology.  Third  Edition.  The  most  Popular  Stu- 
dents' Book.  By  Gerald  F.  Yeo,  M.D.,  F.R.C.S.,  Professor  of 
Physiology  in  King's  College,  London.  Small  Octavo.  758 
pages.  321  carefully  printed  Illustrations.  With  a  Full 
Glossary  and  Index.  See  Page  3.  Cloth,  3.00;  Leather,  3.50 

Brubaker's  Compend  of  Physiology.  Illustrated.-  Fourth 
Edition.  Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

Stirling.  Practical  Physiology,  including  Chemical  and  Ex- 
perimental Physiology.  142  Illustrations.  Cloth,  2.25 

Kirke's  Physiology.  New  i2th  Ed.  Thoroughly  Revised  and 
Enlarged.  502  Illustrations.  Cloth,  4.00;  Leather,  5.00 

Landpis'  Human  Physiology.  Including  Histology  and  Micro- 
scopical Anatomy,  and  with  special  reference  to  Practical  Medi- 
cine. Third  Edition.  Translated  and  Edited  by  Prof.  Stirling. 
692  Illustrations.  Cloth,  6.50;  Leather,  7.50 

"  With  this  Text-book  at  his  command,  no  student  could  fail  in 

his  examination."  —  Lancet. 

Sanderson's  Physiological  Laboratory.  Being  Practical  Ex- 
ercises for  the  Student.  350  Illustrations.  8vo.  Cloth,  5.00 

Tyson's  Cell  Doctrine.  Its  History  and  Present  State.  Illus- 
trated. Second  Edition.  Cloth,  2.00 

PRACTICE. 

Roberts'  Practice.  New  Revised  Edition.  A  Handbook 
of  the  Theory  and  Practice  of  Medicine.  By  Frederick  T. 
Roberts,  M.D.  ;  M.R.C.P.,  Professor  of  Clinical  Medicine  and 
Therapeutics  in  University  College  Hospital,  London.  Seventh 
Edition.  Octavo.  Cloth,  5.50  ;  Sheep,  6.50 

Hughes.    Compend  of  the  Practice  of  Medicine,    sd   Ed. 

Two  parts,  each,  Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

PART  i.  —  Continued,  Eruptive  and   Periodical  Fevers,  Diseases 

of  the  Stomach,  Intestines,   Peritoneum,  Biliary  Passages,  Liver, 

Kidneys,  etc.,  and  General  Diseases,  etc. 

PART   n.  —  Diseases   of   the   Respiratory    System,    Circulatory 

System  and  Nervous  System  ;  Diseases  of  the  Blood,  etc. 

Tanner's  Index  of  Diseases,  and  Their  Treatment.  Cloth,  3.00 
"  This  work  has  won  for  itself  a  reputation.  .  .  .  It  is,  in 

truth,  what  its  Title  indicates."  —  N.  Y.  Medical  Record. 

PRESCRIPTION  BOOKS. 

Wythe's  Dose  and  Symptom  Book.  Containing  the  Doses 
and  Uses  of  all  the  principal  Articles  of  the  Materia  Medica,  etc. 
Seventeenth  Edition.  Completely  Revised  and  Rewritten.  Just 
Ready.  321110.  Cloth,  i.oo;  Pocket-book  style,  1.25 

Pereira's  Physician's  Prescription  Book.  Containing  Lists 
of  Terms,  Phrases,  Contractions  and  Abbreviations  used  in 
Prescriptions,  Explanatory  Notes,  Grammatical  Construction  of 
Prescriptions,  etc.,  etc.  By  Professor  Jonathan  Pereira,  M.D. 
Sixteenth  Edition.  321110.  Cloth,  i.oo;  Pocket-book  style,  1.25 

*S~  See  pages  2  to  5  for  list  of  New  Manuals. 


STUDENTS'   TEXT-BOOKS   AND  MANUALS.        13 

PHARMACY. 

Stewart's  Compend  of  Pharmacy.  Based  upon  Remington's 
Text-Book  of  Pharmacy.  Second  Edition,  Revised. 

Cloth,  i.oo;  Interleaved  for  Notes,  1.25 

SKIN  DISEASES. 

Anderson,  (McCall)  Skin  Diseases.    A  complete  Text-Book, 

with    Colored   Plates   and   numerous   Wood    Engravings.     8vo. 

Just  Ready.  Cloth,  4.50;  Leather,  5.50 

"  We  welcome  Dr.  Anderson's  work  not  only  as  a  friend,  but  as 

a  benefactor  to  the  profession,  because  the  author  has  stricken  off 

mediaeval  shackles  of  insuperable  nomenclature  and  made  crooked 

ways  straight  in  the  diagnosis  and  treatment  of  this  hitherto  but 

little   understood  class  of  diseases.     The   chapter  on  Eczema   is 

alone  worth  the  price  of  the  book." — Nashville  Medical  Neius. 

"  Worthy  its  distinguished  author  in  every  respect;  a  work  whose 
practical  value  commends  it  not  only  to  the  practitioner  and  stu- 
dent of  medicine,  but  also  to  the  dermatologist."— James  Nevens 
Hyde,  M.D.,  Prof,  of  Skin  and  Venereal  Diseases,  Rush  Medical 
College,  Chicago. 

Van  Harlingen  on  Skin  Diseases.  A  Handbook  of  the  Dis- 
eases of  the  Skin,  their  Diagnosis  and  Treatment  (arranged  alpha- 
betically). By  Arthur  Van  Harlingen,  M.D.,  Clinical  Lecturer 
on  Dermatology,  Jefferson  Medical  College;  Prof,  of  Diseases  of 
the  Skin  in  the  Philadelphia  Polyclinic.  2d  Edition.  Enlarged. 
With  colored  and  other  plates  and  illustrations.  i2mo.  Cloth,  2.50 
Bulkley.  The  Skin  in  Health  and  Disease.  By  L.  Duncan 
Bulkley,  Physician  to  the  N.  Y.  Hospital.  Illus.  Cloth,  .50 

SURGERY. 

Jacobson.  Operations  in  Surgery.  A  Systematic  Handbook 
for  Physicians,  Students  and  Hospital  Surgeons.  By  W.  H.  A. 
Jacobson,  B.A.,  Oxon.  F.R.C.S.  Eng. ;  Ass't  Surgeon  Guy's  Hos- 
pital ;  Surgeon  at  Royal  Hospital  for  Children  and  Women,  etc. 
With  199  finely  printed  illustrations.  1006  pages.  8vo. 

Cloth,  $5.00;  Leather,  $6.00 

Heath's  Minor  Surgery,  and  Bandaging.  Eighth  Edition.  142 
Illustrations.  60  Formulae  and  Diet  Lists.  Cloth,  2.00 

Horwitz's  Compend  of  Surgery,  including  Minor  Surgery, 
Amputations,  Fractures,  Dislocations, Surgical  Diseases,  and  the 
Latest  Antiseptic  Rules,  etc.,  with  Differential  Diagnosis  and 
Treatment.  By  ORVILLE  HOKWITZ,  B.S.,  M.D.,  Demonstrator  of 
Anatomy,  Jefferson  Medical  College  ;  Chief,  Out- Patient  Surgi- 
cal Department,  Jefferson  Medical  College  Hospital,  sd  edition. 
Very  much  Enlarged  and  Rearranged.  91  Illustrations  and 
77  Formulae.  i2mo.  No.  q  ? Quiz-Commend ?  Series. 

Cloth,  i.oo;  Interleaved  for  the  addition  of  Notes,  1.25. 

Pye's  Surgical  Handicraft.  A  Manual  of  Surgical  Manipula- 
tions, Minor  Surgery,  Bandaging,  Dressing,  etc.,  etc.  With 
special  chapters  on  Aural  Surgery,  Extraction  of  Teeth,  Anaes- 
thetics, etc.  208  Illustrations.  8vo.  Cloth,  5.00 

Swain's  Surgical  Emergencies.    New  Edition.  Illus.  Clo.,i.5o 

*S"  See  pages  15  and ibfor  list  of  ?  Quiz-Compends  f 


14        STUDENTS'   TEXT-BOOKS   AND   MANUALS. 

Su  rge  ry  ; —  Con  tin  ued. 

Walsham.  Manual  of  Practical  Surgery.  For  Students  and 
Physicians.  By  WM.  J.  WALSHAM,  M.D.,  F.R  c.s.,  Asst.  Surg. 
to,  and  Dem.  of  Practical  Surg.  in,  St.  Bartholomew's  Hospital, 
Surgeon  to  Metropolitan  Free  Hospital,  London.  With  236 
Engravings.  See  Page  2.  Cloth,  3.00;  Leather,  3.50 

THROAT. 

Mackenzie.  Diseases  of  the  (Esophagus,  Nose  and  Naso- 
Pharynx.  By  Sir  Morell  Mackenzie,  M.D.,  Senior  Physician  to 
the  Hospital  for  Diseases  of  the  Chest  and  Throat ;  Lecturer 
on  Diseases  of  the  Throat  at  the  London  Hospital,  etc.,  with 
Formulse  and  93  Illustrations.  Being  Vol.  n,  complete  in  itself, 
of  Dr.  Mackenzie's  text-book  on  the  Throat  and  Nose. 

Cloth,  3.00;  Leather,  4.00 

"  It  is  both  practical  and  learned  ;  abundantly  and  well  illustrated ; 
its  descriptions  of  disease  are  graphic  and  the  diagnosis  the  best  we 
have  anywhere  seen." — Philadelphia  Medical  Times. 

Cohen.    The  Throat  and  Voice.    Illustrated.  Cloth,  .50 

James.     Sore  Throat.     Its   Nature,  Varieties  and  Treatment. 

i2mo.     Illustrated.  Paper  cover,  .75;  Cloth,  1.25 

URINE,  URINARY   ORGANS,  ETC. 

Acton.  The  Reproductive  Organs.  In  Childhood,  Youth, 
Adult  Life  and  Old  Age.  Sixth  Edition.  Cloth,  2.00 

Beale.  Urinary  and  Renal  Diseases  and  Calculous  Disorders. 
Hints  on  Diagnosis  and  Treatment.  i2mo.  Cloth,  1.75 

Holland.  The  Urine,  and  Common  Poisons.  Chemical  and 
Microscopical,  for  Laboratory  Use.  Illustrated,  ad  Edition. 

Cloth, .75 

Ralfe.  Kidney  Diseases  and  Urinary  Derangements.  42  Illus- 
trations. i2mo.  572  pages.  Cloth,  2.75 

Legg.     On  the  Urine.    A  Practical  Guide.     6th  Ed.    Cloth,  .75 

Marshall  and  Smith.  On  the  Urine.  The  Chemical  Analysis  of 
the  Urine.  By  John  Marshall,  M.D.,  Chemical  Laboratory,  Univ. 
of  Penna  ;  and  Prof.  E.  F.  Smith,  PH.D.  Col.  Plates.  Cloth,  i.oo 

Thompson.  Diseases  of  the  Urinary  Organs.  Eighth 
London  Edition.  Illustrated.  Cloth,  3.50 

Tyson.  On  the  Urine.  A  Practical  Guide  to  the  Examination 
of  Urine.  With  Colored  Plates  and  Wood  Engravings.  6th  Ed. 
Enlarged.  i2mo.  Cloth,  1.50 

Bright's  Disease  and  Diabetes.     Illus.          Cloth,  3.50 

Van  Niiys,  Urine  Analysis.    Illus.  Cloth,  2.00 

VENEREAL  DISEASES. 

Hill  and  Cooper.  Student's  Manual  of  Venereal  Diseases, 
with  Formulae.  Fourth  Edition.  i2mo.  Cloth,  i.oo 

Durkee.    On   Gonorrhoea  and   Syphilis.    Illus.      Cloth,  3.50 
-93-  See  pages  15  and  ib  for  list  of  ?  Quiz-Compends  * 


NEW  AND  REVISED  EDITIONS. 

PQUIZ-COMPENDS? 

The  Best  Compends  for  Students'  Use 
in  the  Quiz  Class,  and  when  Pre- 
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Compiled  in  accordance  with  the  latest  teachings  of  promi- 
nent lecturers  and  the  most  popular  Text-books, 

They  form  a  most  complete,  practical  and  exhaustive 
set  of  manuals,  containing  information  nowhere  else  col- 
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large  experience  as  quiz-masters  and  attaches  of  colleges, 
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form,  and  the  size  of  the  books  is  such  that  they  may  be 
easily  carried  in  the  pocket.  They  are  constantly  being 
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can  be  used  by  students  of  any  college  of  medicine,  den- 
tistry or  pharmacy. 

Cloth,  each  $1.00.     Interleaved  for  Notes,  $1.25. 

No.  i.  HUMAN  ANATOMY,  "Based  upon  Gray."  Fourth 
Edition,  including  Visceral  Anatomy,  formerly  published 
separately.      Over   zoo   Illustrations.      By  SAMUEL  O.   L. 
POTTER,  M.A.,  M.D.,  late  A.  A.  Surgeon  U.  S.  Army.     Professor 
of  Practice,  Cooper  Medical  College,  San  Francisco. 
Nos.2and3.    PRACTICE  OF  MEDICINE.    Third  Edition. 
By  DANIEL  E.  HUGHES,  M.D.,  Demonstrator  of  Clinical  Medi- 
cine in  Jefferson  Medical  College,  Philadelphia.     In  two  parts. 
PART  I. — Continued,  Eruptive  and  Periodical  Fevers,  Diseases 
of  the  Stomach,  Intestines,  Peritoneum,  Biliary  Passages,  Liver, 
Kidneys,  etc.  (including  Tests  for  Urine),  General  Diseases,  etc. 

PART  II. — Diseases  of  the  Respiratory  System  (including  Phy- 
sical Diagnosis),  Circulatory  System  and  Nervous  System;  Dis- 
eases of  the  Blood,  etc. 

***  These  little  books  can  be  regarded  as  a  full  set  of  notes  upon 
the  Practice  of  Medicine,  containing  the  Synonyms,  Definitions, 
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disease,  and  including  a  number  of  prescriptions  hitherto  unpub- 
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(OVER.) 


BLAKISTON'S  ?  QUIZ-COMPENDS  ? 

Continued. 
Bound  in  Cloth,  $1.00.  Interleaved,  for  Notes,  $1.25 

No.  4.  PHYSIOLOGY,  including  Embryology.  Fourth 
Edition.  By  ALBERT  P.  BRUBAKER,  M.D.,  Prof,  of  Physiology, 
Penn'a  College  of  Dental  Surgery  ;  Demonstrator  of  Physiology 
in  Jefferson  Medical  College,  Philadelphia.  Revised,  Enlarged 
and  Illustrated. 

No.  5.  OBSTETRICS.  Illustrated.  Fourth  Edition.  By 
HENRY  G.  LANDIS,  M.D.,  Prof,  of  Obstetrics  and  Diseases  of 
Women,  in  Starling  Medical  College,  .Columbus,  O.  Revised 
Edition.  New  Illustrations. 

No.  6.  MATERIA  MEDICA,  THERAPEUTICS  AND 
PRESCRIPTION  WRITING.  Fifth  Revised  Edition. 
With  especial  Reference  to  the  Physiological  Action  of  Drugs, 
and  a  complete  article  on  Prescription  Writing.  Based  on  the 
Last  Revision  of  the  U.  S.  Pharmacopoeia,  and  including  many 
unofficinal  remedies.  By  SAMUEL  O.  L.  POTTER,  M.A.,  M.D., 
late  A.  A.  Surg.  U.  S.  Army;  Prof,  of  Practice,  Cooper  Medical 
College,  San  Francisco.  Improved  and  Enlarged,  with  Index. 

No.  7.  GYNAECOLOGY.  A  Compend  of  Diseases  of  Women. 
By  HENRY  MORRIS,  M.D.,  Demonstrator  of  Obstetrics,  Jefferson 
Medical  College,  Philadelphia.  In  Press. 

No.  8.  DISEASES  OF  THE  EYE  AND  REFRACTION, 
including  Treatment  and  Surgery.  By  L.  WEBSTER  Fox,  M.D., 
Chief  Clinical  Assistant  Ophthalmological  Dept.,  Jefferson  Med- 
ical College,  etc.,  and  GEO.  M.  GOULD,  M.D.  71  Illustrations,  39 
Formulae.  Second  Enlarged  and  Improved  Edition.  Index. 

No.  9.  SURGERY.  Illustrated.  Third  Edition.  Including 
Fractures,  Wounds,  Dislocations,  Sprains,  Amputations  and 
other  operations;  Inflammation,  Suppuration,  Ulcers,  Syphilis, 
Tumors,  Shock,  etc.  Diseases  of  the  Spine,  Ear,  Bladder,  Tes- 
ticles, Anus,  and  other  Surgical  Diseases.  By  ORVILLE  HORWITZ, 
A.M.,  M.D.,  Demonstrator  of  Anatomy,  Jefferson  Medical  Col- 
lege. Revised  and  Enlarged.  77  Formulae  and  91  Illustrations. 

No.  10.  CHEMISTRY.  Inorganic  and  Organic.  For  Medical 
and  Dental  Students.  Including  Urinary  Analysis  and  Medical 
Chemistry.  By  HENRY  LEFFMANN,  M.D.,  Prof,  of  Chemistry  in 
Penn'a  College  of  Dental  Surgery,  Phila.  A  new  Edition,  Revised 
and  Rewritten,  with  Index. 

No.  ii.  PHARMACY.  Based  upon  "  Remington's  Text-book 
of  Pharmacy."  By  F.  E.  STEWART,  M.D.,  PH. G.,  Quiz-Master 
at  Philadelphia  College  of  Pharmacy.  Second  Edition,  Revised. 

Bound  in  Cloth,  $1.    Interleaved,  for  the  Addition  of  Notes,  $1.25. 


These  books  are  constantly  revised  to  keep  tip  with 
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printed  and  bound.  Each  one  forms  a  complete  set  of 
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